Its been posted a billion times before, that it's effectively an automatic rifle... but comparing the rifle and the SMG right now... I'd say they're roughly even in a firefight. A slight damage nerf at WORST is what would make it more balanced at long range, but as it is, it's more or less still balanced.
I thought it was OP before, but then I thought about how an alternative model might look (a change in accuracy/firing rate) and felt it was unnecessary.
So, no, I don't think the SMG needs a dynamic nerf (a small, straight nerf to damage would be fine), and I'd be perfectly fine with it staying how it is.
Either way, we should be focusing on the current 'shit' weapon.
The shotgun.