If you're playing against a retarded ape.
The very first thing decent players do nowadays when playing against sov is rush t1 and pump out 2 atgs. Just one contact with the enemy and t70 is a burning pile of metal. It's even better with OKW since they have t0 ATG.
My point being: sure, T70 is a deadly tank for its price, but it has become so commonplace it lost its edge by the sheer number of players using it.
T70 pre nerf was better at AI than T34-76. Now it more blance.