As is, the SMG falls short. It does pitiful damage, hits jack and the recoil is silly.
Furthermore, the low damage output means that while with either rifle or shotgun you can kill the enemy instantly without retaliation fire, smg has a tendency to leave you below 50 health after a single kill, if you don't shoot people in the back.

I'd suggest either increasing damage, accuracy or reducing the recoil.
Personally I'd prefer increasing headshot damage.

And finally, I'd like to see the terrain destruction capability to be shifted more over to the shotgun.