Re Q2, sucks to see the bubble shield nerfed so hard for what already was a unit I'd rarely see. Using mass costs for simplicity, before it was 7600 mass (2100+2000+3500) for a 55k shield [i.e. 7.2 shield per mass] that would (when discharged or down) regenerate at 256 health/s (150 when up).
Now it's 5200 mass (1700+3500) for a 22k shield [i.e. 4.2 shield per mass] that would (when discharged or down) regenerate at 200 health/s (160 when up).
As a comparison, Sera T3 mobile shield although significantly smaller, benefits from far better speed of 4 (2.2 for the SACU), and costs 720 mass for a 10k shield [i.e. 13.9 shield per mass] that when down regenerates at 250 health/s (133 when up).
In terms of potential value from a UEF perspective, a percy gets 5.6 health per mass investment; granted this shield protects from aoe damage, but at the same time it also takes damage faster because it's easier to hit with indirect projectiles (far more so given its size compared to other mobile shields).
Before the shield was so high in health that it could both be used as an alternative for base defences in some scenarios (e.g. I found it made a good tele defence for smd/arti/game enders compared to static shields where a SACU could teleport in and its death explosion could kill the static shields), and was an option for covering slower attacking units with the defensive buff justifying delaying the army a bit. The shield would recharge painfully slowly and coupled with the slow SACU speed it was difficult to get continued value from them (compared to mobile shields).
Now it feels like that's been made even harder - it still has the really slow speed compared to other mobile shields, but no longer has the high health to compensate. It's also (vs single target damage) more efficient to just get percies vs getting a mix of percies and shield SACUs. I presume the intention is therefore for it to no longer be used primarily as a shield unit, but instead as a hybrid combat-shield unit, but also one where the increase in damage spill means it's worse in numbers (with its large shield size harming building it in larger numbers disproportionately compared to the other mobile shields, since it's more likely to overlap with other shields; the bulwark would be a useful counterpoint for where a high shield size can still work, but the bulwark is significantly faster and the shield size so large it doesnt need to be on the frontline). But if it's only intended to be built as a single unit to support an army, it then works out even more inefficient unless the gateway was being built for other SACUs (maybe the wider SACU changes mean it would be). So I expect I can still use it for teledefence (cheaper vs SACU tele, weaker vs tele-laser), but other mobile shield uses for it feel much weaker.
Appreciate you primarily wanted in game testing, whereas I usually approach things from a more theoretical 'if I had the apm to use this unit however I wanted, what use cases can I see for it', since I can then both have my AI apply those use cases, and use them myself as a player occasionally. However I'm really struggling to see how I'd be better off building percies, a gateway, and 1 or more of the bubble shield units vs just building percies (given the shield gives less health than the percy),
Also just checking how things compare at the t2 mobile shield stage re shield health vs combat unit health, t2 mobile shield gives 3k health for 220 mass (while being fast moving and recharging much faster). A pillar gives 1500 health for 198 mass. It's a similar story for othuums - i.e. T2 and T3 mobile shields give significantly more health per mass invested than an equivalent combat unit, compared to the new bubble shield SACU which gives less (so maybe its combat potential makes up for this, but then it's less of a mobile shield than before, when the rationale for the change was that it was being rebalanced with mobile shields in mind?)