Well I guess it's not a waste of time if you like them. Though I think MMORPGs would work better if they employed something like Oblivion, you have a main quests and sub quests but there is always that feeling of closure - even in smaller quests and through a way that does just rely on text - and the so-called 'epic' battle should have more to them than CLICK CLICK CLICK CLICK,HEAL, CLICK, CLICK, CLICK, DEAD. Woohoo 500,000 exp!
Though what I really find a waste of time about MMORPGs is the constant walking - gaps in environment that do nothing, yet seem to be there to make it look bigger. I'd actually prefer the worlds if they were smaller. (In some, the evironment is over scale - a door is 3 times the size of the player - I guess the characters are pixies?)
However, I still like playing Runescape - yeah the game play isn't brilliant compared to retail games, but I don't have to walk travel insane distances before reaching something interesting. And of course you can do a lot in it - though there isn't that feeling of closure. At least with Runescape it's big, because it's big, there are a lot of places to visit and the gaps aren't that big between places.
"Experience never provides its judgments with true or strict universality; but only (through induction) with assumed and comparative universality." - Immanuel Kant