I think it would be a good change to have the cost of a new t3 mex and the cost of a t2 mex plus a t3 mex upgrade be equal. Having high apm is already very beneficial in FAF without this added bonus. We don't need to further handicap low apm players with an additional ~700 mass penalty per t3 mex compared to their higher apm counterparts.
Suggestion: remove "t2 to t3 mex rebuild" game mechanics maybe?
Except that it involves floating the required mass, spending time moving engies, and finding the time to go back to mexes every 30-50 seconds. Being mad that proper planning gets you an eco advantage might as well as mean removing tree groups so people properly planning around them don't get rewarded for their "apm" as well.
There are times where it's worth ctrl+k'ing mex, and there are times where it is not worth the additional mental overhead. If it is always worth it in your games, you're playing big teamgames where aggression is not a concern and you got like 10 mex to babysit.
ok I can see this mechanics can be one of the aspects of mastering the game (when to do or not to do ctrl+k instead upgrade)
Still I don't like this overcomplicated technique.
In my opinion it looks like a bug that become feature. Since it exists in FAF for ages and people get used to it i doubt that it will be ever changed. But it is very counterintuitive and may lead to accidental ctrl+k of something valuable like already rebuilt t3 mex or even comm. When i started to play FAF i legit had to make ui mod just to make sure i won't ctrl+k something else 
My only problem with this exploit is that it seems non-intuitive, and it’s not something that could be effectively conveyed in a loading screen tip
put the xbox units in the game pls u_u
Cost to build t2 mex - 900 mass
Cost to upgrade t1 mex to t2 mex - 900 mass
Cost to build t2 radar - 180 mass
Cost to upgrade t1 radar to t2 radar - 180 mass
Cost to build t3 UEF shield - 3300 mass
Cost to upgrade t2 shield to t3 shield - 3300 mass
The "counterintuitive" aspect is adding a weird rule to t3 mex upgrades. The game is perfectly consistent. The only area the game doesn't work like this is support factories.
It's rare that people will upgrade a lot of radars, but it's normal to upgrade multiple support factories and mexes.
It's only fair to make people pay extra for the privilege of upgrading a shield in place when a certain faction can't even do that at all.
It just comes down to this: do we want to give people the option to do a little song and dance, to trade APM in exchange for about 600 extra mass? Or do we want to streamline the game here.
I'm definitely in favor of streamlining the game by equalizing the cost of upgrading in place vs. ctrl-k trick. The game is complicated enough. Making it a little simpler here is more good than bad.
@greensubmarine said in Suggestion: remove "t2 to t3 mex rebuild" game mechanics maybe?:
In my opinion it looks like a bug that become feature. Since it exists in FAF for ages and people get used to it i doubt that it will be ever changed. But it is very counterintuitive and may lead to accidental ctrl+k of something valuable like already rebuilt t3 mex or even comm. When i started to play FAF i legit had to make ui mod just to make sure i won't ctrl+k something else
I had problems accidently cntrl+k things I didn't mean to so what I do now when I use this technique (very rarely) is I just use my engies to reclaim the mex then build the t3 so there is no risk to make that mistake.