I was trying to think back to all the MMO's I've played, and I can't remember one that's kept it's freshness past the first Expansion. Generally the core game is the best, and the first expansion add's a lot of cool new elements and zones, races classes so on and so forth, but after that it generally just gets to the "these zones are for the advanced players" and just keeps the grind going.
No thanks. The BEST thing DAoC did was create a server specifically for the classic game and the first expansion. I wish WoW had a server like that, where it would just be azeroth without any of the Burning Crusade or beyond anything in it. Ya know, maybe two or three servers like that, I'd probably go back and play but eh.