The new D&D is too rule intensive. It's relegated the Dungeon Master to being an entertainer rather than master of the game. It's done away with the archetypes, focused on nothing but combat and character power, lost the group cooperative aspect, bastardized the class-based system, and resembles a comic-book superheroes game more than a fantasy RPG where a player can play any alignment desired, not just lawful good.
GameSpy interview, Pt. 2 (16 August 2004)