My own personal thoughts as someone who has never played WoW but other MMOs (mostly GW2, Archeage, XI and a sprinkling of WildStar..RIP):

I can sort of see where the comments are coming from regarding XIV being "too cute" and along those lines. I think a big part is that our races generally fall into categories of model-esque, or just super adorable. They're all rather safe looking, nothing too grotesque or ugly about them.

Then the world itself - I personally like XIV's styling, I think it's quite pretty. But you don't really have too many totally wasted areas, or gory scenes scattered about. I was running through AA recently on a new character with a XIV buddy, and I was remarking how this one area I was questing in was rather grim with all the dead bodies and blood scattered about - to which I got a reply along the lines of "that's actually fairly common, just not in XIV".

I can't really speak for the story, but things seem to tie themselves up into neat little packages. AGAIN, I DON"T READ IT SO I COULD BE VERY WRONG HERE. However, it feels like the WoL is untouchable, the "main" players are untouchable. What on earth will it take to finally kill Minfilia?!?

I think those are the main items for me, may be more if I sit here and think about it some.