It is the global problem about burst weapons (maybe i'm wrong, but it is how I feel it.)
Big guns are good, because of their range & suppression. And they deal good damage at good range.
The burst weapons have the same power wherever is your target, juste in front of you or 40ex away (as long as you stay in the eff range). Basically, theses weapons should be much more powerfull at short range (more bullets hits at short range->more dmg). But it's not the case. It's a choice the dev's made, I respect that.
And that's why smg's are uselless. They are outclassed by pistols/shootys at short range, because the burst dmg don't increase with the proximity of target.
(again, maybe i'm totally wrong, but i feeld it like that)