Well, to start off, Final Fantasy does not hold a candle story wise to any of the previous games so I would most likely not count that. Personally, I did not connect with the characters in Dragon Age as much as I did in Mass Effect.  They are so much more relatable and humane. If you were to chooses one, I would choose Mass Effect :)

Well, i personally as a fairly new WoW player think it is totally worth going back to. The MoP expansion pack hasn't neccesarily brought everything with it that players wanted but I for one find the Pandarens great! (Though the kids are a little creepy 'Hey, you wanna play?...' Even if you don't have the expansion, the update still brought plenty of new stuff. However, i wouldn't recommend coming back and continuing a high level character as environments may feel unfamiliar if you haven't been online since before cataclysm , but if you have feel free to keep playing with this character and experience loads and loads of new content.