First off, as much as I love being able to take out Fleshpounds with a single bolt now, it's terribly overpowered. Make it like it was before the patch, where it could take three or so bolts before it went down.
The Sharpshooter's drawbacks (Pre-update) were the lack of ammo and the lack of any sort of crowd-control ability. Everyone, save the Medic (I never played the Beserker much, so I can't really speak on his behalf, but he seemed to be decent at keeping large crowds at bay) has some decent ability to take out large mobs. The basis of a Sharpshooter is to have a TON of firepower, but only able to concentrate it on a single point. The addition of the M14 has really taken care of these drawbacks. I mean, I love the M14, I LOVE having to not worry about ammo, but 14 mags? I don't even have to bother with a sidearm now!
Now, I don't play on Suicidal.. yet. The difficulties have become much harder with the new update, so Normal and Hard are pretty challenging to me. The M14 fills a niche that needed to be filled, and I can't really suggest what to do with it, other than to maybe cut some of the ammo from it, so that Sharpshooters are somewhat dependent on their sideams/teammates to help clear out the ZEDs.