I've played D&D for a long time and I've thought every edition has improved the game. But I'm genuinely worried about D&D Next.
From what I've read so far it seems like the overriding goal is not to make a new version of D&D, but to make a unifying version, something that appeals to fans of all the previous editions. I don't see how they are going to make everyone happy.
Each edition has had innovations in it that have completely changed the game. That's one of the reasons I've felt that each edition has been better and why each edition revitalized an interest in playing for me. So far I don't see anything mentioned by the design team that has anything NEW. Love or hate 3.x or 4e, both games were radical revisions that introduced multiple core concepts to the original game that were game changers. 3.x introduced attacks of opportunity, feats and skills as core to the game design. 4e introduced healing surges, a large pool of encounter powers for all classes, healing as a minor action while still getting to perform an attack action in the same round. Playing the new edition was an exciting, new experience for me because it was a completely differerent experience than ever before, but still D&D.
If the upcoming D&D Next was a musical release it would be a "best of" album with remixes from various old albums, but where are the original song tracks? My fear is that I see D&D next being a clunky hybrid system pooling from all the editions, but with only limited truly unique innovations. This runs a risk of peeling a fragment of players from each edition camp, but ultimately a large amount of gamers sticking with their favorite game, and further fracturing the D&D community even more.