Blizz adds content slow, the size of the island is tiny, and the architecture is just Silvermoon City 2.0.

plus alot of it was buggy on release, and theyve broken several things with their patching (RAWRRARRRARGH! if you dont know what that means, your not playing WoW right now).

While its an interesting island, the development cycle is just too long, its a big complex patch, but even lotr, vanguard, DAoC, EQ all release bigger patches more often that fix things and add new content.