I'd actually just like to see another pass on combat, since it's the main part of gameplay. For whatever reason, it's wearing thin to me lately. Doing the same thing in a new place is still doing the same thing. The main gameplay challenge is seeing through the massive blur of effects to find the 5% of the screen that isn't covered in orange circles. Other than that, though, positioning isn't well-utilized due to most AoE skills being simple circles. Too much emphasis on gimmick mechanics that are walled off from core build mechanics, rather than having a strong integration between the two, which would encourage more variety in tactics and builds. PvE needs more emphasis on tactical reaction, and less on rotation. OW and story encounter design is based on solo biffing or mindless zerging, mostly. Even though they are the most accessible means of teaching players, it's never well-utilized for, e.g., teaching non-DPS builds or things that will help players function better in the more challenging game modes. More thought should be given to having mechanics that scale better from solo(ish) to party to raid-squad to zerg, without being shallow or trivialized at any level.