WEll I think ISU is the main incentive for players to go towards Mechanized. It is one of the few doctrines with mark target. Although I think bombing strike will be a lot more effective now?
I think the IS-2 is fairly weak against armor, especially those KTs and JTs. Hopefully the nontracking thing isn't a bug. I am worried this will pigeon players into even lesser commanders (those with shocks and IS2).
IS-2 is surprisingly good against the KT, and expect to see less JT to counter it. Any commander with shocks has always been good, and my roster usually consists of Lend Lease, Counterattack tactics, and the IS-2 shocks and incendiary strikes. Call ins as usual, but the ISU always felt like cheating when i build T2, spend no fuel until the CP comes, and then call in ISU after ISU which counters near all.