I'm not making a judgement on 5 man Grenadier squads, pro or con but if they were to be implemented (big if I know) why not tie it to vet like USF's RE instead of a global upgrade?
This way not all Grens would automatically get 5 men and it would reward squad preservation into the late game, which is the name of the game.
Just a thought.
I don't think 5 men gren squads are a good idea. We all know what three gren squads with lmg42s a-moving can do. If they get a 5th man, they get too powerful.
I rather think that the other infantry units need to be towed down to the effectiveness of Grens. Mind you, riflemen and tommies should still be better, but only slightly. This goes for conscripts too.