There are a lot of reasons I prefer this to WoW. For the record, I played WoW from cataclysm (Firelands(4.2)) through the Timeless Isle patch in Mists. I have (sub lapsed, but they still exist) four 90s (warlock, paladin, death knight, and mage) and a handful of others at lower levels. All geared well for when I was playing.
With that out of the way, here are mine in no particular order:
* Final Fantasy allows me to play all of the classes without having to log into an alt.
When dealing with gear drops that aren't tradeable this is awesome. I hated getting a drop on my paladin that my lock needed and just having to suck up not being able to do anything about it.
* Final Fantasy has no-grief gathering.
Some people like fighting for resources but I don't. Being able to go out and gather without having someone else swoop in and take a node out from under you is a huge plus.
* The graphics of FFXIV are so much nicer.
* There is no open world pvp.
I know some people want it, but the way WoW did it it was a grief fest.
* Duty locked mobs.
Much like gathering nodes, having a quest mob that someone can't hijack (and thus make the quest take longer) is a nice feature.
* Assisting in killing open world mobs counts in quests and for the hunting log.
WoW has a tag system that makes the mob belong to the first person to hit it. Meaning that players in some zones (Looking at you outlands) have to sit around and hope that they're faster on the trigger finger. Here, if they tag it, that's no big deal. As long as I participate, I get credit.
* More animated emotes
Small thing but nice.
* The community is nicer
No. Really.
EDIT: Also this:
All isn't sunshine and roses though. There are a few things I wish we had from WoW.
* Less onerous crafting system.
I know that ARR's crafting system is an improvement over previous incarnations of the game (or so I've been told at least), but it's a pain in the rear overall.
* More toys!
WoW has had ten years to build up a collection of nonsense/vanity items and I miss that huge pool. I know the game will get there in time.
* Pet battles.
I'm going to cry foul on this. A huge amount of Mists was gated behind faction dailies. You had to grind tillers dailies to unlock your farm, which was necessary to increase faction rep elsewhere. You had to grind golden lotus to get access to certain gear and enchants and I think to open up access to yet another faction grind. Mists was mad with daily locked content, even more than FF is.