Here's how I'd implement an RPG:
-Heavy weapon, can only be used by the heavy body type
-Can only load one rocket at a time, and you have four rockets max (1/4 ammunition count, same as the lobster)
-Fires in a straight line, instead of having the dropping arc that grenade launchers do
-Detonates on impact
-Does the same damage as the lobster on explosion, with a slightly larger radius and enhanced knockdown/knockback effect
-Reloads slightly slower than the lobster
I dont want the carl gustav in this game, even with as many triple kills as I got with that thing during my time playing bf:bc2 =P Explosive/AoE weapons should be more for the crowd control effect than damage output.
I'd say similar to this, but slightly higher damage than the Lobster, and a smaller blast radius - RPGs are meant to be anti-armour, not crowd control. Range and damage are better than normal GLs, but it's Heavy-only, limited ammo, and smaller AoE.
EDIT: By the way, I voted "no" but basically the closest options to what I described here for all the "if it was in" questions - I don't think it's a totally stupid idea, because there's the maintenance bot argument, and they'd take those down faster than most weapons if implemented the way I'm suggesting. But the idea of rocket launchers and RPGs in a game with so few vehicles is pretty silly, really. I'm not saying a definite "stupid idea" though - it's interesting, and could be fun, but I don't feel like it's a weapon you really need - it would be more situational than the Barnett and Lobster are.
As long as any weapon they include is one requiring skill, I'm going to be happy.