Infantry squads have paper for armor, that's what is implied in INFANTRY!
^Not a real argument, but whatever.
THe germans have plenty of options for wiping infantry. In fact, the germans have 3 nondoctrinal units to do so. The Brummbar has the exact same AOE value as the ISU, and it has a vet artillery strike. Then there is the Panzerwerfer, which fires 12 rockets at a single position from far range, and is usually either a wipe or heavy damage to any infantry in the area. Finally, there is the Sturmtiger, which can instawipe very large concentrations, shoot through buildings, and even cripple/ instagib vehicles. Germans have plenty of options, they just usually don't bother to use them in most games because they prefer to use Tigers.
EDIT: sorry, forgot to respond to everything: The Stuka can wipe squads with a single rocket, which is not hard to hit because it is deadly accurate.
Your comparisons are just plane wrong.
The ISU doesn't have a range of 40, like the Brummbär, thus you can easily avoid tank combat. You also seem to forget that bigger 6 men squads are rarely getting wiped.
The ISU, also doesn't have a reload of at least one minute, so you can't compare it with the Sturmtiger.
Same goes for panzerwerfer and stuka. High reload & can't spot for themselves. Especially the panzerwerfer needs to be driven close to the enemy in order to do any damage because of that horrible scatter.
I like the changes because it removes the units out of the game. No longer you can park your super unit behind a wall of at guns and mines and safely destroy the enemy force.
Now the emphasis lies again on tank combat, micro and baiting.
The ISU and Jagdtiger feel just out of place in the CoH mechanics.