So I know that a lot of you are probably worried about the SAMW as a primary weapon and think every noob will just run around using it the whole time. I personally don't think this is likely because HVS, if they are smart, will require you to use currency to buy it first, and hopefully will make it cost quite a bit of currency. This would solve the noob tube problem everyone is complaining about, and since they are really trying to balance everything, I think it is likely that this is what theyll do.
Launchers (rocket and grenade both) are secondaries in MW2. You can also get separate grenade launcher attachments on your primaries.
On its own, this isn't horrible. Explosive weapons in MW2 are balanced by having extremely restrictive ammo counts, either one or two shots total depending on the weapon. As you don't (normally) reload your weapons from corpses, if you don't die fast then this can be a pretty steep price.
The problem is that one of the first perks you unlock effectively removes this ammo limit by letting you reload everything from corpses. With Scavenger active, launchers almost immediately go from being a one or two shot weapon to being infinite ammo as long as you can safely run near a corpse between shots. I don't recall if the Pro version's boosted mag size applies to either or both launcher types as well, but the damage is already done with the base version's reloading.
Weapons and perks simply aren't particularly well balanced in MW2. Not everything is game breaking, but there are things off seemingly at most levels of design.
Help is a gift that one must never grow to expect. -- Willow (Witches' Brew by Terry Brooks)