I'm one who firmly believes that the game published in 2000 was not a new edition of [A]D&D but a wholly new game using the D&D trademark. Following from this, 3.5 was the 2nd edition of that new game (that I sometimes refer to as "d20 Fantasy). For the sake of community, I try not to mention this belief unless a topic specifically elicits this response. So whatever the next edition contains, it isn't D&D to begin with, IMO.
As for 4D&D: for the most part, I find myself in favor of the changes being made to how the d20 system is carried out throughout the rules framework. More attention seems to being paid to ease of play/preparation, for example.