the only last really problematic thing in this game imo is the 120mm mortar and its 1-man retreat
I don't know if it's #1 but adding up with the rest of guard motor it is devastating.
I don't care what some players say, the 120mm is imbalanced in terms of damage and viability. Especially as Ost you can not kill this thing, it's just not possible unless your opponent is asleep. Counter barrage doesn't work, flame barrage doesn't work and even a squad of Panzergrens won't take it down fast enough.