I'm the player who first suggested the issue to Iron Guardian, because at the time, I didn't have an account here at Mongoose. Now, I know the two suits sound similar, and perhaps they are, but this is my argument for them being seperate. Close Support and Assault are different roles, even in todays military. Where an assault trooper is your standard soldier, with a rifle, sidearm, knife, and maybe a few grenades, the support trooper usually carries things like heavy explosives, or emplaceable machine guns. Even in Call of Duty, the support class uses the big machine gun and C4, where the assault trooper has an M16 and grenades.
Aside from the massive difference between the launchers (Semi-auto with 18 rounds total/Fully auto with 96 rounds total), the close support battle dress comes with a built-in computer: Computer/2 running Expert Tactics (military)/2. That's an expensive add-on. So in terms of price, the Assault Battle Dress would also be much cheaper, though hopefully with the same or better armor protection and stat boosts...