I just bought a 6-month subscription last week and upgraded my account for WoD. I gave the free boost to my 75 Belf Pally, which was the first Horde char I ever leveled past 40.
As alot of folks have said already, I'll try out WoD and see how it goes. I got the 6-month sub so play through the summer, which is when I use the Midsummer EXP Boost to level my alts faster. I have heirlooms too but every little bit helps XD
Honestly, I've grown weary of the MMORPG genre.
Depending on how I like WoD this might be the first time I don't level cap a character in a new expansion. I skipped most of MoP due to real life obligations and a rapidly shrinking player base server side. I play GW2 as well and I can tell you the feeling's more of the same with folks I've been talking to there. A big difference is A-Net rolls out new content at just the right pace to keep most folks interested. I also played SW:TOR when the free version was decient and have logged a few weeks total in Second Life, RuneScape and Everquest I and II.
I think the thing more and more MMO Vets have come to accept in recent years especially is they've grown up. No longer do they have the time to commit to MMORPGs they once did and that's ok. Life goes on. Luckily for everyone, the MMO Industry planned for this inevitable and will keep your chars forever in case you decide to come back down the road.
I won't say I'm done with WoW since I've said that twice in as many years and have come back a third time now. I don't think I'll be playing WoW by this time next year due to burnout but once I've decided for sure I won't make a "retirement" thread or blog post. My time in WoW will have ended the same way it began: Uneventful with no one there. That's how it should be XD