T3 nerf to bring it in line with the rest of the tech tree was an indirect buff to T4. Games between competent people shouldn't have experimental ping pong anyway. I mean, there is no ping pong between large groups of t3 either. Simply too much of a mass investment to throw away in a "ah yeah maybe it'll do damage lol" attack.
In fact the ping pong between
- player masses up t3 push and takes map control
- other player puts mass into a t4 concentration
- Other player retreats to build up a larger t3 mass to defeat t4 or retreats to get his own t4
Is more of the ping pong situation you describe.
One example would be a dude pushing with a mass of snipers/shields, meets a fatboy, has to retreat to some sort of firebase/own t4 to push and tank fatboy with/needs some major clump of t3 that can tank the fatty.
Also a lot of underselling of the balance team here lol. The GPG balance was absolutely terrible in this game. In fact, I'd go so far as to say that the balance in base supcom/FA was SO bad it's actually a fundamental reason why the game failed to garner any sort of real competitive scene. It had so many inconsistencies with tons of the unit rosters being either useless or bonkers OP with no real thinking needed to choose between options. Nothing that has happened due to the T3 rebalance has really been "unexpected" in the sense of broad meta strokes. Well, maybe the huge efficiency of t3 mobile arty wasn't accounted for. T4s may or may not need a slight adjustment in their stats, I personally don't think they do and enjoy their purpose in the current meta.
Would rather nerf garbage like RAS SACUs.