Well... I dunno about the weapon balance issue. A lot of people liked how OP some of the weapons could be. Admittedly, that makes PvP a pain in the ***, but I wasn't much of a PvP player, anyway. For me, it's the endgame content. It's the same reason I loved FFXI for so long. Getting that Outbreak Prime felt like an accomplishment, especially because of the tedium.
I'll second the Outbreak Prime! "XB1: Looking for Titan for OP9" haha
I am hoping for a few things. One is better in game chat in Destiny 2 (should be easy on PC). It was frustrating finding people to play with on the LFG sites. But when I finally found a regular group on the100 and this wasn't as much of a problem.
Another thing which would be super fun is cross platform play. I would like to play on PC with my brother on Xbox One and our friend on PS4. For those KB + Mouse vs Controller arguments, maybe they could make Trials (if it is in Destiny 2) platform specific. But honestly, I'll suck either way, and would just like to play with family and friends!