The grenades we just did. Those are CQC weapons.
They're not primary weapons. Given the choice between going to battle with only an SMG or only a pair of grenades, a soldier will choose the former.
Given the choice between going to battle with only an SMG or only 50 grenades though...
But yeah, your arguments make sense (a bit, at least), but I'm still not convinced that is our primary need RIGHT NOW. We'll see how grenades work out.
And as for rockets, we could make simple RPGs by revising our AT grenades proably, as we have our rocket mortar and all we need to do is to basically attach rocket to grenade.
But then, I think we should wait and see how things work out.