That's because Bungle is unable to balance shit in a bowel, not because PvP wasn't fun.
Also, the guns weren't even op. Suros for example was just good. Every weapon should've been that way. But they destroyed the whole weapon class because of that one gun. Same with the Vex. That thing was op...but instead of toning it down a bit, they destroyed all Fusion Riifles. Wrong nerf after weong nerf led to the desaster we're playing right now...and D2 is even worse.