Proposition, remove SACU upgrades entirely, instead have a selection of uniquely balanced units for different intended roles.
The main reasoning for doing so is simple, it would significantly boost freedom to tweak and balance each type of SACU. For example, instead of having to give every SACU the same base movement speed and the same upgrade giving the same regen boost, one could easily choose rambos to move slower but have even higher regen, support units to move faster but have slightly lower regen, or any veriation their of.
As a secondary benfit, it also streamlines and standardizes the process of picking and building units, making it fit the already well established methodology used in all other factories.
Besides, there is never any good reason to go and get, for example, a ras preset and resign all the upgrades into a rambo. Just go and build another rambo, it would be faster, cheaper and easier.

Ok thats the big thing out of the way, now for smaller balance details.

UEF engineering upgrade is largely redundant. If you need lots of build power over long range, build kennels. If you need the ability to start building t3 buildings anywhere on the map, just use a transport to move t3 engies or the SACU its self. If you do want to have the SACU to have engie drones, then at least cut it down to one upgrade teir instead of two.
I am all in favor of faction diversity, but in this exact case functionality has been sacrifeced to for the cause.

The base stats of unupgraded SACUs are absurdly high. This was fine before, but now with the intention of lowering them down to fit in with t3 land, being able to build a non experimental unit with a hp over 15k and high regen ontop is excessive. Additionally, the fact that only Aeon SACUs can be one hit killed by overcharge is a bit unfair. Lower the hitpoints of all factions unupgraded SACU to 15k or less.

Remove Aeon sacrifice upgrade and instead give it as an addition to the engie upgrade for no extra cost. Sacrifice is simply way to neiche to justify its existance as a seperate upgrade, ontop of being largely redundant (Two mutually exclusive construction upgrades, just why?)

Buff or replace seraphim SACU TML upgrade. Getting SACUs into play happens much later then getting T2 TML laucnher meaning its much eaiser to counter SACU missiles, they also cost significantly more to build and are semi redundant because you can just use the SACU to build TML laucnhers anyway. As it stands they have very little reason to use instead of other options.
I prepose a few possible changes:
Massively boost the range of the SACU TML so that it substantually out ranges T2 TML.
Buff stats of the TML projectile to differenciate from the t2 version (More missile hp, faster travel speed, larger AoE, EMP effect, stuff like that)
Replace the ability to build TMLs with a MML weapon, kind of like a land equivilent of the seraphim crusier.

Although you are right that the numbers dont line up, there is a significant detial you have missed, spesifically the fact that UEF nano regen ocupies the same slot as the engineering upgrades while the seraphim one doesnt. That is part of its 'cost' that you have to later replace it.

The perpose of the UEF nano is to be an early game boost to combat effectiveness, at the expense of being unviable in the late game, because of this it is cheap and does not allow the constructuon of t2 buildings.

The seraphim nano is the exact oposite, its intended as a more late game boost to surviveability without sacrificeing early game capacity.

Atlantis, a shallow (pun not intended) attempt at faction diversity. Of could have just been given a t3 carrier like everyone else but instead they got a t4 just to be different. But then it would be too different, so instead they got a t3.5

That roughly sums up the whole problem, the Atlantis doesn't know what it wants to be, a t3 aircraft carrier or a t4 submarine, so it tries and fails to be both at once.
It's not a good carrier because its mass cost per BP is over twice as much as other carriers, in fact it's literally cheaper to build a t3 air HQ from scratch if you want t3 air units.
It's not a good submarine because its massive size, slow speed and relatively low hp make it a pitifully easy target to destroy.

The only thing going for it are its relatively cheep cost for a t4 unit, and its decently powerful weapons.
Essentially it is a glass cannon, a quick to build but short term boost to firepower. A gimped monkey lord.

There are a few options on how to rectify this:
Take a heavier focus on the submarine aspect, make it a little smaller, boost its speed, add some anti torpedoes. Make it threatening to enemies naval units.
Take a heavier focus on its carrier aspect, give it much more build power, more powerful AA, maybe even Airstaging (if adding that to a submersible unit doesn't break everything).
Turn it into a dedicated support unit, a t4 cruiser wannabe, using its AA and torps to discourage incoming attacks to your navy while offering extensive sensor range and fighter support.

Jamming could be put into UEF SACUS at base (cant waste a slot if it doesnt take a slot!) but that does leave a gap in the support for preset and I can't think of anything useful to add there that isnt just a basic stat up like extra sensor range. I suppose there could be a 'high intensity jamming' upgrade that just amps the jamming effect up to 11.

Short list of some small potential changes to discuss:

SACUs only have access to t1 and t2 unless they have the engineering upgrade which grants them t3 t4 as well as extra BP. At the very least it would force UEF to get the engie upgrade if they want to Rav creep.

Engineering upgrade gants extra build radius (discussed on the discord a while back https://discord.com/channels/197033481883222026/1236147386141904988).

Gateway adjacency changes, maybe even including changing the size to fit more or less adjacent buildings (Would 8 t3 adjacent fabs be overpowered, or is that enough risk of a chain reaction plus setup cost to be fair?)

Nerfing RAS so the mass generation goes from +10 to +5 (ontop of base +1 from the SACU) but also lowering the cost to the payoff time is the same, but now you need to spam twice as many to get the same total income, meaning you have ~twice as many things to defend from incoming fire, which combined with the base health nerf should mostly satisfy people complaining about ras bois being op.

Removing the income generation of SACUs without RAS entirely so now your not paying for uneeded stuff when building rambos.

Some upgrades cause SACUS to death nuke harder, things like teleport or gun upgrade, thigs that you wouldnt get unless you are expecting them to end up in enemy territory.

Replacing Sera overcharge upgrade with a Refracting Chronotron Amplifier so multiple can be used at once without needing infinite energy.

This is the ideal time to discuss large scale changes to the whole plan of SACUs since that is literally what we are doing, and changes to eco and reclaiming can be a part of that.
But lets not turn this thread into a discussion on what can or cant be in this threat, lets just discuss SACU changes.

I do not agree with the removal of RAS entirely, RAS boi spam is already in many ways inferior to mas fab farms, and the base health of SACUs is getting heavily nerfed so that is an indirect nerf to RAS bois anyway.

Underwater reclaiming is in the same situation, the base health AND base build power of SACUs is getting nerfed so they will now die faster and reclaim slower.

I could see a movement speed penalty when underwater being applied, but then you run into the problem of why do SACUs have this penalty but not other things? The ACU is even bigger, should it not get slowed down even more?

As for giving gateways the nuke treatment (~10x the build power, ~10x the build time) that could be done, but feels kind of antithetical to the primary goal of this thread, to make them more common, not less common.

Sera shield has its uses outside of tele, it is most certainly a good upgrade, costing Less than half the mass cost of the unit for more than doubling its health. It is just held in obscurity by the unviability of SACUs themselves. The total removal of it without adequate compensation would greatly hurt the unit overall.
Seras SACUs are in a bit of a uniqe position currently as their higher base damage, no RAS and some of the strongest combat upgrades, both offensively and defensively, push them into being the most combat focused SACU of any faction, a feature that I do think would be worth keeping in mind for the rebalance.

Jamming could be put into UEF SACUS at base (cant waste a slot if it doesnt take a slot!) but that does leave a gap in the support for preset and I can't think of anything useful to add there that isnt just a basic stat up like extra sensor range. I suppose there could be a 'high intensity jamming' upgrade that just amps the jamming effect up to 11.

Probably a bad idea, but why not include cloaking in all cybran presets? Stealthy engies for sneeky building or risky reclaiming. Stealthy rambo to shoot without being shot back, stealthy support option in whatever form that ends up taking. It fits in any situation just about.

As for what the support upgrade could do... I really hate to say it but a regeneration field fits them well, too well, even better than it fits Sera. All their stuff regens faster than other factions anyway, their nano repair upgrades have rediculious regen rates, they even got hives which are practiaclly a stationary regen field already, they lack mobile shields so they have an open slot for a mobile defence field. They even have a building that in the lore explicitly creates a nanobot field around it (Soothsayer).

It would not be an identical copy of the seras regen field as sera would also have the max health boost, but I can understand if the overlap is decided to be too much.

The other other things that make any faction sense are radar stealth field (redundant, although having a t3 deciver wouldnt be the worst thing ever). A cloaking field (extremely overpowered unless we give omni out like free candy). And EMP, which Aeon have nabbed first.
Edit: It has occured to me that personal cloaking with a radar stealth field would actually be highly versatile but not overpowered. That would be an excellent support option.

@thewheelienoob said in SACU Rebalance:

1000 mass is nothing at that point of the game so everyone would just opt for the stronger nano

The cost is entirely beside the point, it was just an example.

Been thinking furthur about the implications of the changes (as presented so far) for Sera SACUs, and I have concluded that the nano repair upgrade would do well to be split into two levels, similar to the ACU version.
As an example, if the first level cost approximately 1000 mass 40 seconds BT and the second cost approximately 2000 mass 120 seconds BT, it would allow player choice between cheaper faster deployed rambos, or full strength comparable to nano+shield rambos, while also maintaing faction coherence.

I am concerned about the complete removal of Seras personal shield, or more spesifically the 20k drop in max effective health that would give telesacus, that is a very significant nerf to one of the signiture strategies of lategame Sera. Are there any plans to compensate for this?

In my earlier post I suggested removing all upgrades completely, but it seems some people have interprited what I said as haveing different themed SACUs each with their own set of upgrades. For example, a 'base engineering' SACU with low hp, low damage and no combat upgrades, but is cheap, has high BP and upgrades for things like faster build speed, longer build range, RAS, extra mass/energy storage.
And I have to say, I like that idea more. A lot more.
By giving players the ability to build for example a 'base combat' SACU at the gateway that has stats compareable to t3 units but then can be upgraded furthur as needed still gives players some freedom to customize SACUs while still maintaing most of the upsides mentioned before.

Now ontop some other points I desire to be clarified if possible.
Seeing as all SACUs (at least currently(ignoreing the engie drones)) are land units, are there any plans on expanding their impact in air and naval play? Other than spambuilding SAMs/HARMS and reclaiming they really serve nearly no purpose for either.

What is the high end of strength to be expected for SACUs? The low end has been clearly set as to around t3 land, but how much stronger will they get after that with full upgrades, will we start see SACUs 1V1 GCs and winning? David meet Goliath.

Are gateways intended to only a lategame option, or will gateway rushing become a viable strategy to deplay? For example, suppose a player went T1 and T2 land but skipped T3 and went right to building combat and combat-support SACUs to use as the heavy land units.

Proposition, remove SACU upgrades entirely, instead have a selection of uniquely balanced units for different intended roles.
The main reasoning for doing so is simple, it would significantly boost freedom to tweak and balance each type of SACU. For example, instead of having to give every SACU the same base movement speed and the same upgrade giving the same regen boost, one could easily choose rambos to move slower but have even higher regen, support units to move faster but have slightly lower regen, or any veriation their of.
As a secondary benfit, it also streamlines and standardizes the process of picking and building units, making it fit the already well established methodology used in all other factories.
Besides, there is never any good reason to go and get, for example, a ras preset and resign all the upgrades into a rambo. Just go and build another rambo, it would be faster, cheaper and easier.

Ok thats the big thing out of the way, now for smaller balance details.

UEF engineering upgrade is largely redundant. If you need lots of build power over long range, build kennels. If you need the ability to start building t3 buildings anywhere on the map, just use a transport to move t3 engies or the SACU its self. If you do want to have the SACU to have engie drones, then at least cut it down to one upgrade teir instead of two.
I am all in favor of faction diversity, but in this exact case functionality has been sacrifeced to for the cause.

The base stats of unupgraded SACUs are absurdly high. This was fine before, but now with the intention of lowering them down to fit in with t3 land, being able to build a non experimental unit with a hp over 15k and high regen ontop is excessive. Additionally, the fact that only Aeon SACUs can be one hit killed by overcharge is a bit unfair. Lower the hitpoints of all factions unupgraded SACU to 15k or less.

Remove Aeon sacrifice upgrade and instead give it as an addition to the engie upgrade for no extra cost. Sacrifice is simply way to neiche to justify its existance as a seperate upgrade, ontop of being largely redundant (Two mutually exclusive construction upgrades, just why?)

Buff or replace seraphim SACU TML upgrade. Getting SACUs into play happens much later then getting T2 TML laucnher meaning its much eaiser to counter SACU missiles, they also cost significantly more to build and are semi redundant because you can just use the SACU to build TML laucnhers anyway. As it stands they have very little reason to use instead of other options.
I prepose a few possible changes:
Massively boost the range of the SACU TML so that it substantually out ranges T2 TML.
Buff stats of the TML projectile to differenciate from the t2 version (More missile hp, faster travel speed, larger AoE, EMP effect, stuff like that)
Replace the ability to build TMLs with a MML weapon, kind of like a land equivilent of the seraphim crusier.