I like the idea of the "smoke grenade", however I believe it looks more like a shield drain type of weapon. Which is not exactly new to Halo, as we've seen the shield drain in 3, but none the less, it would be fun to use again.
It pretty much is the portable turret.
Except it has no kick, does not slow you down, and is a first person weapon oppose to a third person perspective weapon. It seems slightly more powerful than the AR, and already has me pooping in my freshly fastened adult diapers.