With WoD in a month, what do you feel will happen in to FF14's population?

[Fyrebrand]

What is WoD?

This was me, too, at first. I had to think about it. "Warriors of Dynasty?" "World of Ducks?"
I did eventually realize OP was talking about Warlord of Draenor, the next WoW expansion. But the fact that he never actually bothered to spell it out, and just assumed everyone magically knew what he was talking about, seems a little pretentious.

WoW with updated its graphics which is almost comparable to FF14

Uh... the updated character models are neat, but in my opinion are still fairly dated. I don't see how it is even close to FFXIV, graphically.

Anyway, to answer your original question: I can't speak for what others will do. It's likely that some amount of people will want to try out the new WoW expansion, but I won't be one of them. I quit for good after Cataclysm. Pandas did not entice me, and neither does what they're offering now. In fact, since the game has that limited free trial (play til level 20, I think), I actually went back and played around in WoW just for old time's sake. It's actually pretty jarring, after playing more modern MMORPGs. It felt very awkward to play, and the experience quickly dissolved whatever nostalgia I had left for the game. Blizzard can apply as many facelifts they want, it doesn't change what's underneath.