I have been reading and thinking about 4th ed D&D for a while now. And while I am not as annoyed or anxious as I was initially, I still have reservations. I understand that Wizards must continue to produce new material for existing games, and new editions of existing games, but I felt that it was a little too soon for a new edition, still do really.
If the improvements to the game are not as significant as the improvements made by 3.5 or even 3.0 then I will be disappointed with the new edition. And by improvement I do not mean changes, I mean improvements, changes with substance that will make the game better.
Also, I am very disappointed in the decision to make major changes in how the OGL works. A partner and I have been working on a setting that I eventually want to publish but with the new rules and new edition I will probably have to wait almost a year to do so.
Over all my remaining complaints have less to do with having to buy new books, I own well over 300 gaming books and don't mind getting more, though I don't like buying the same book over and over if I can avoid it. I really felt that with 3.x the D&D game had the best ideas for a fantasy system that is going to use levels and classes*. It has a very nice, and playable fusion of the classic d&d/ad&d feel with the sophistication of game mechanics and concepts that have developed over the last few decades.
I will give 4th edition a chance, but I really hope that it wow's me. For a good nutshell description of the changes try this blog or go to ENWorld.
* I prefer the idea of a point based system, as it seems more organic. The best example I can think of is Hero system. More on that system another day.