The subject has already been beaten to death already and if someone has already posted my suggestions then well...they beat me to it. But here are some ideas to help make the dreaded "n00b t00bs" much more bearable in online play.

1. As the game stands, you can only hip-fire with it. Hip-firing with all the other remaining weapons significantly cuts down in range and accuracy with a trade-off for speed. Why not the same with the M-203/GP-25? As they were in Call of Duty 4 and Modern Warfare 2, they are seemingly precision weapons when fired from the hip! Decreasing accuracy to that of a lobbing mortar weapon (as would be the real life affect of shooting them that way) would be a good balance while keeping it as a good support "softening up" artillery weapon.

2. You can implement the method of making it only usable if you aim down the sights with it. Forcing the player to flip up the leaf sight and then having to slow down to a walk and aim with the launcher would be a good balance that could negate the balance suggestion #1. Then precision shooting would make sense with the thing while aiming and reloading would be slower. Modern Warfare 2 made this true with the M79, so why not the successive launchers attachments?

3. In either firing from the hip or aiming down the sights, there should be sway like that in the usage of the sniper rifles. AR's were designed to fire in the hand positioning to shoot the bullets, and grenade launchers are attachments to the already existing rifle. Therefore, the hand positioning in their usage is not the most perfect (at the same time not absolutely awful)compromise to have a steady platform. Especially with how the character does it with the FAMAS, does anyone notice that he puts both hands on the pistol grip? Their has to be sway from that.

Anyway, thanks for reading. I hope this was an insightful post for somebody out there =D