Well, late to the party, but with a bit to say:
WoW had a couple of advantages that gave it a nice boost as well:
A: Blizztard made it. They probably had a couple or more peeps on board that had a clue, and had other games raking in steady piles of moola to keep the WoW devs pizza-fied and chained to their workstations nice and proper.
B. They had 3 prequels to lay down story and make people think they were playing Warcraft 4 and get a huge player base started.
3. They're dirty cheats. You can't rub 100 players together before they squirt out some new servers. Big loss in my eyes, not being able to have a larger player base and more broadly based. I know that you can't have an extremely dense player concentration in that world, but I would challenge them to find a way to allow for higher populations and more international diversity.
D. Any game that offers MASSIVE amounts of people to play together, imho, helps us all, (gamers that is). It brings us together so that we can compare notes, expose each other to new ideas, and help evolve as players and as influences in future games.
E. There is lots and lots of room for games to add both simpler content for the 12-yr olds, while still allowing the DIE-HARDS room to have their brain bashing fun. The real obstacle there, (imho, yet again) is the consumers themselves. As long as there are whiny prats and griefers to prey upon them, there will be 'The game is too hard!!!' and 'There's no challenge left, I got to 80 in 3 DAYS!!!' The trick is getting the balance right. Would a group of level 80 Deathknights gather regularly if they discovered a magical pool that transports them to a differnt plane if they're all wearing wedding gowns where they'll be battline level 90 dragons for a chance to get an uber weapon that will never take damage? HELLS YEAH!!!!
6. Who's gonna make it? I don't know of many companies like Blizzard that have a solid following of a product and deep pockets to do what they've done. That being said, is it going to come from an indy source? We've seen some browser games do a pretty good job of dragging people in, they just need to get hooked up with the right business people and grow it up into a full-fledged game perhaps. Our job is to help them by playing the good games, and giving up on the ones we can't stand the smell of after 3 days on the coffee (or tea) table.
There's games for every taste. I've loved FF for years, but haven't gotten around to FFXI. I loved Eve, but technical issues and playtime took me away from it. Now technical issues and time are fighting me again and have taken me away from WoW, but inadvertantly gotten me to work on drawing a comic strip for a summer project with my kids. But the MMO's of the world have brought many of us here, together, where we wouldn't be without them. Playing together is a helluva lot better than where we could be without them!!!! Here's to the next MMO that I CAN play!!!! Even if it's one I've played before!
Ok, as I read back through, I realize my focus went all wonky, but meh, daughter had a meltdown midpost, and it's not bad post-fodder, so I'll leave it!