I have been into WoW on and off since Vanilla/The Burning Crusade.
From my experience I can tell you, you may enjoy it for a while then it will die down. The new expansion Mist's of Pandaria is ridiclous in my opinion and i have wasted £30 on it. If you are still thinking about playing it i recommend trying a private server giving that a go, and the trial of the official WoW see how you're computer handles it and see how you enjoy it.
It will come to a point where the game is just rinse and repeat.
In my opinion once again WoW will never be the same game as it used to be and joining WoW at this time would be a bad move.
These are just my thought's remember, it all comes down to you.
If you do decide to play I believe I still have a running subscription on my account and I can help you out if needed. My main character's are on the Europe side of Ravencrest.