To give honest input about the Great WoW Exodus, there's this: People who stick through the MSQ story into Heavensward will be the ones that adapted to FFXIV being much more story based.
I actually joined this game on a lark, as I am sure some of my fellow Azerothians have. I tooled around on the trial and realized I wanted to play this more than I did WoW. So I moved here full time as my new MMO.
FFXIV seems less polished to me. The long global cooldown takes many Azerothians (WoW players) by surprise and it takes a very long time to adapt to. The user interface is clunky. The server-dictated live state can make this game unforgiving with a crappy internet connection.
And yet...
What I saw here was something we haven't seen in WoW for over a year: Effort! Real, genuine effort! Someone somewhere loves this baby.
I could go on and on about what's turning people away from WoW of late but the abridged version is this: Activision owns Blizzard and has turned the big cash cow into a massive Skinner Box. WoD is very clearly built around operant conditioning and not much else. Lots of players have been comparing it to an iPad game and they aren't wrong. iPad games make a ton of money in today's market and ActiBlizz obviously wanted to use their tricks to keep people logging in. To a degree they succeeded since WoD was indeed compelling. It compelled you to play. It was not at all engaging, however. Many veteran players are realizing there is no art in it anymore, so some leave and some stay because better the devil you know.
FFXIV is engaging. For all the faults I see in it that aspect of it blows modern WoW out of the water. The characters, world, story, content, all feels meaningful in a way nothing in WoD does. So for now, at least, we can be expecting WoW players to come here. Do not expect them all to be jerks or want the game to be made shallow. Some might but lots of them are here because it's different and has the art and love behind it that their game used to have.
TL; DR Moral of the story: WoW players are coming but they don't want to make this game into the one they just left. They want something different to remind them what fun is.