Personally I just really want to see soft- / preferential-targeting implemented with melee skills able to go off so long as you have any applicable enemy within range (though always showing range according to your set target and always using your set target when it's in range). And, ideally, for every skill that looks like it should be at least partially an AoE to be one to that extent.

Tab targeting shouldn't need to be nearly so large a part of the game. On controller especially it feels like it has practical design constraint conflicts with rapid repositioning for melee DPS skills and really holds back intuitive and efficient button-mapping.