TBC took out a lot of casual gamers. I played original a lot but the time consumption for TBC was just too much for me with school. TBC = Endless farming and it lost its sparkle pretty quick after the raids became the same old shit. The next Ex pak will just be more time consumption with more of the same old raids. I would think the lore to be getting pretty thin at this point unless they whip out northrend/deathwing/kiljaeden or something. I suppose they can always make stuff up. I would say WoW has one more expansion left in it but after that I think that the player population will dramatically decrease due to the time consumption raise and other MMOs being released. It would wiser to focus purely on a new diablo game if they are interested in fat cash. If any game could break WoW's MMO record for numbers.... D3 would be the one.