An exciting feature set, delivering just what everyone wanted.
However that all changes with The Burning Crusade! I have not been as excited to log in and play on my level 60 Rogue so much since he was level 59! Some people feel the need in games like this, to be the number one, and to get to the top of everything as soon as possible, however I prefer to have something to accomplish, and thats where the level 70 cap, and the new outlands come in.
If you don't have a high level character, TBC can feel a little empty, for people level 20-58 the only new content available to them is Jewlcrafting. However if they start a new character from either of the new races, they will find a wealth of new low end content available to them.
All in all, I feel that The Burning Crusade is an excellent addition to the World of Warcraft, and I expect it will keep me, and many like me, addicted to game for a long time to come.
How long until The World of Warcraft has 10 million customers? Not long, I'm sure.