What is the problem with the 5 men Grenadier in t4 again?
Besides the fact that a doctrine already does this, they'd be the highest DPS infantry squad and presumably still only cost 240mp to build. (Plus you could still presumably add the LMG42 to the squad... you quickly run into the situation where this single squad could be doing something like 20 DPS at max range.)
I was specifically looking for non-combat buffs since I think replaceability is a major issue for Ostheer infantry considering their high reinforce costs and the absence of any survivability veterancy until vet 3.
I should have clarified, however, that I think the sbps pop cap reduction should be a stock thing (I'm not sure it's actually a bonus which can be granted midgame in any case). Grenadiers having the same population cap as 5-men infantry squads (or conscripts for that matter) seems a bit off to me.