I think the OP is asking the wrong questions. Iys not whether or not another game will ruin FFXIV's chances. To me its always been whether or not SE will ruin FFXIV. SE is SE's worst enemy. They just love to do things their way, and players be damned if they don't lap it up. I really want this game to succede, and I have been since launch in a perpetual state of Hope but not commitment to this game. And everytime the Devs do something great, it seems they have to do something disappointing. Its like for every 3 steps forward they take 2 steps back. Will the game eventually get to a place where I can say "This is my MMO addiction for the next 7-10 years"? Possibly. But the real question is can they do it before I decide I am tired of them making /facepalm decisions and all of my LS members leave me? Patch 1.18 lost me 5 LS mates. Ive beaten both the new dungeons multiple times, and now logging in is beginning to feel like a chore again. Something I make myself do in the hopes the next patch will magically fix my problems with the game. Am I crazy? Perhaps. But I feel I am out of options, and here is why:
1. Console/gamepad friendly
2. Deeper Storyline.
3. Heavy PvE

There is simply no other choice (aside from FFXI, been there done that). So I must cling to the hope that FFXIV will get better and better, eventually becoming a game I can be happy to play for the next 7-10 years, or hell even longer.