Game genres have certain games that have set the standard for what those games should feel like. For example most FPS today feel like Halo or CoD why because those games set the current standard for FPS. When I play any FPS that isn't one of those games I get the same feeling and similar controls. When I sit down to play a 2d fighter it plays like Street Fighter, when I play a 3d fighter it usually plays like Tekken or Vitura Fighter. When I play a turn based RPG I expect something like the Final Fantasy games.

FFXIV was so broken at the beginning and didn't follow a lot of the basic mechanics that were already set by WoW and other similar MMOs that people just didn't like it. From animation lock to exp system that did work right randomly get SP some times you didn't other times SP gain would totally break and you have to relog, to a UI that was unresponsive and sluggish at best, very slow paced and unresponsive combat, lack of any kind of end game, no AH and people being told to look through hundreds of retainers for what they want to buy. FFXIV 1.0 was just way below the game industry stranded for MMOs. People left very fast cause of it. 1.0 wasn't some holy grail of originality it was a lot of broken stuff.

A problem with MMOs is people go through content very fast. SWTOR from what I heard didn't have enough stuff to do when you hit level cap. People very much liked the leveling process and all the voiced stuff they did but once you hit level cap people ran out of stuff to do. WoW on the other hand has a huge amount of endgame to do. Part of it has to do with their budget on these type of games. Because Blizzard has so many players they can afford to have a lot more content. It may be only every 6 months but when they release a content patch keeps players busy for quite awhile.

Another thing is attachment in WoW a lot of people get attached to their game they might try out other games when they are bored with the current patch on WoW but then they always go back to WoW when a new patch drops to try out the new content that gets added, since they already built up a lot of characters even more reason to go back.