I think assgren is just too weak for their cost. They should at least making an upgrade from MP40 into STG44 in later stage of the game.
Their nades are worthless, their guns are total shit unless 0m range. All Soviet have to do when spotting assgren is to run, gather and blob cons together behind cover.
They can't even do a nice job like MP40 volks protecting flanks of MG42.
I want to agree with you, and in some games I do. Like VS Shock Troops. But AssGrens are pretty good coming out early game. It doesn't take too much micro managing to exterminate any enemy squads in game.
For example I usually go with 3 AssGren squads, use grenades, micro manage them into cover, and kill any enemy left.
Are you a CoH1 player? If so, I think I know where your criticism is coming from. We just can't BLOB our close quarter combat troops like we could with Pio Spam, PanzerGren spam, etc. they die much quicker in CoH2. CoH2 you have to treat your AssGrens as actual people that NEED cover.