Wut? do you really think massing T70 would counter a KT? Massing T34-76 yes since it is the purpose of that change but I don't expect T70 or Stuart doing more than today.
But to cut short this discussion, it is not about thinking what an actual T70 would do but how to modify any damage/armor relationship for any vehicle.
If armor only reduces damage then mass T-70 would work the same way mass PTRS works.
T-34/76 can still be very effective is they attack rear/side armor.
Another change is that is units should have cool-down after their being destroyed.