If you ask for "skill tree", you'll get emotional answers (as proved by nearly everything above my post). It's better to generalise and ask for "customisation" and play on the fan-service chord because customisation if obviously a strong aspect in many previous FF. It's hard to ask for something with well-pondered reasons, it's better to use something easy as fan-service.

Since the devs of ARR, who are already playing much with fan-service to sell their game, decided to not work much on customisation even though it could be a strong fan-service aspect, I don't think we should expect much from them. It's not something that can be added quickly/easily.
Of course, customisation is (should be...) a foundation of a RPG, but depth in a game is hard to sell (as proved by previous posts with answers like "I can't think by myself and build my own char so I'll just have to read guides to be accepted."). A 5-stars chat room like ARR is good enough.