Why need T4? T3 and the right commander is enough to deal with many things. T4 is just the extra stuff for a long game/big team game.
this. now the biggest obstacle for ostheer t4 is that their t3 is just very efficient and potent. i honestly think even if getting to t4 cost as same as going for t3, like the current soviet tech, i would choose t3 most of the time in most cases.