On a purely statistical tack, I don't think any of the weapons currently in the game are broken overpowered. The HVR is far too effective in a variety of ranges, the N-TEC invalidates everything in the AR and Rifle classes and the OCA is pretty stronk in the SMG class(if only by virtue of the PMG being just outright worse than it) but thats been the state of the game since as long as I can remember. Those guns are strong in their respective classes, the HVR is strong in general though and I think thats the biggest problem honestly. Having greater useable weapon variety would be nice though and I think eliminating "Jack of all trades, master of all" weaponry would be a solid step in the right direction.
There are certain weapons that are just statistical upgrades or reshuffles of base game progression weapons though, the VBR Huntress and OCA Whisper come to mind. That content I think needs to either become accessible to all players(As part of base game progression. Joker Tickets function as an additional gate to content, which I think is unnecessary) or just cease to be.
EDIT: Oh and the Yukon. Yeah.