No, just add teching requirements. Zero tech tanks need to be removed.
Umm, this is exactly why they are called call-in tanks.
They arrive much later already then you could have the armor if you've tiered.
Only thing currently being wrong is soviet tier armor being so bad that there is literally no reason to pay that 140 fuel+whatever more you need to get T34 or SU. A problem ost doesn't have because all of their armor, doctrinal and stock is performing well.