I like both and I play both.
Each has its perks.

When it comes to systems fluidity, lag and general playing speed WoW clearly wins.
When it comes to small group content (seriously WoWs trival dungeon content isn't even eligible for a proper comparison lol) and visuals FFXIV wins.
Also no PvP bullshit is always a + in my book. :P

Can't really compare raiding endgame because I have no experience in FFXIV.

4. Battle System more complex
As far as the classes I play are concerned: I disagree. (BLM / WHM)
I'd say BLM = Mage and WHM = Holy Priest