I 've never really liked the idea of nerfing the T4 units , "so that building them is actually viable". To me nerfing them , equates to messing with t3 and virtually canceling it. You 're not supposed to be able to build them early; they belong to a very advanced "T4" economy, if we can mint this term.Why not build t3 assault bots, t3 artillery, t3 units first? If you build a t4 because you deserve it(economy as a result of strategy-battles) it should be ridiculously powerful as well as expensive.
Beginning of rant
Giving credit to eternal whiners, destroyed supcom2:
1. oh oh too difficult to reclaim, just remove it
2. oh oh the units, have problems in pathfinding waisting computational power, let's replace it with the unnatural flowfield(yupee battleships and colossi skating on ice like ballerinas!)
3.oh my god too high graphics requirements(lol), let's make it look like a toy from the AOE era.
4. whine! my t1 units can't be used in later stages, let's buff them so that a tiny winy mouse can bring down a t4 behemoth(oh yeah the revenge of little people!)
and countless more whines!-end of rant..
Like it or not, supcom can be a lot of different games, from the starcraftesque t1-t2 rush, to the countless hours lasting "nirnaeth arnoediad" over huge maps and militarily established territories. What kind of battle you like to participate in is a matter of personal taste, just don't impose it on others, thus corrupting the essence of the game.Noone would prohibit in this case to accompany your t4 with t3, but it would retain its character of inspiring awe and panic!
Buffing the t4, would expose possible weaknesses of t3(ie if it is possible to win a t3 opponent while you 're at t3 yourself; if you had necessarily to tech to t4 this would indicate imbalance)