I'd say aim assist. Aim assist in d2 is very strong but for a long time bows and hand cannons had the absolute highest when it cam to aim assist even if a hand cannon has like 0 aim assist stat it still will have like 2x more aim assist than most other weapons bows no longer have this which is good but now it's hand cannons turn. A lot of people say hand cannons don't need a nerf because while they're strong they're "tough" to use when in reality they're arguably the easiest which in combination with their power makes them pretty much the top pvp primary every season. I'd say reduce the aim assist not to the point it's the same as other weapons but enough that body shots don't turn into precision hits.

As a hand cannon main, I support it. I would also ask to reduce aim assist on everything though at a similar scale so people actually need to learn to aim on a FPS game.

The issue with that is that the games designed around it. If you have way too low aim assist (Easily achieved by jumping) bullets can pass through enemies. However some weapons have more than they need. Auto's and Pulse could use a very small decrease (And in return buff autos by 5% in pve and 15% for pulse rifles in pve in terms of damage), Hand cannons need a medium decrease (Not sure what to give pve in return), not sure about smgs or sidearms since I don't use em much.

that is a AE issue

The issue is sorta AE the thing is AE reduced aim assist (Both stat and the weapons base) to near 0 and this caused bullets to pass through enemies so bungie reduced the aim assist penalty so it'd stop happening.