Wildstar's problem was that the game was not fun from minute one. Most people I knew logged out of the tutorial spaceship or after a few minutes in the first desert zone. Moving your character around felt bad with the sliding and animations and camera movement and move speed. Mobs have AoEs you need to move out of to simulate action, but again movement feels bad so it doesn't feel good. And then you press a button and hit like a wet noodle only hurting a mob for 15% of its HP bar. It is overall just not entertaining. Whereas you could just play a real action game where it feels good to move your character around, you get cool camera angles or slow mo dodges, you press a button and explode an enemy into itty bitty bits and it feels great, etc. Also, you are clicking on cheap 2D UIs that felt bad even for its time, etc.
WoW's combat and character controls/movement feels better due to the immediate responsiveness, no animation delay, etc. As meh as FF14's gameplay is, at least controlling your character doesn't feel as bad, and there isn't as much AoEing making you run around as much just to fight normal mobs. FF14 also has other things going for it presentation wise such as the story cutscenes or the memorable music, while Wildstar had none of that. Maybe if the original director hadn't been usurped by the art director, it would have turned out better.