Two things, quick:
1- Underwater diving: Why not allowed ? We dont need too much content underwater, but diving and "swimn sprint" would be nice to have.
2- Enemies Model (Hostile NPC's): I know for being a MMO, the model should be the "simpliest" possible for performance pouposes, but the way they die, its too much... the same??? they move like they're not part of a 2014 game, as an archer, it was boring seeing the way they died by the arrows.
Back in Oblivion/Skyrim, i love how they were hit by the arrows, then falling dead, it was more "realistic", i know its different mechanics, but I bet Zenimax/Bethesda could work better on this, being in a modern MMO, i think that for exemple: see (Hitman, Slient Assassin), Mobs acting with freedom body members like that would add more fun to combat.