Count me as another saying that the time was right for a new edition. Not because 3e sucked, although it certainly has its problems, but because there was enough 3pp OGC to offer substantial improvements.
Combats in 3e do tend to take too long, especially as levels increase, and the power curve was too steep (IMHO). 3e's attempt to define everything also made adventure creation seem a bit more like homework than is good for the game. IMHO, game prep should consist of about 80% thinking things up, 10% writing things down, and 10% figuring out how to put things into gamespeak. 3e ended up about 75% figuring out what gamespeak to use. Again, IMHO.
I am not at all certain that 4e has really solved any of these problems......excepting, of course, that a truncated core means truncated gamespeak....at least until the PHB III comes out.
The best side effect of this new edition, IMHO, is that it has opened up a lot of discussion about game design, design goals, and how to achieve them. I don't believe that I fully appreciated/understood Mr. Gygax's work until I compared it to 4e. I imagine that the same is true for some of the folks at WotC, and that 5e will be better for it.
There are a number of really good ideas in 4e as well. Not all of these good ideas are executed as well as they deserve to be, IMHO, but there you go. I haven't yet seen what Ari has done with the material; I imagine it's brilliant, and fixes some of the warts.
If I didn't think it was time for a new edition, I wouldn't have started creating a "new edition" of my own (RCFG). I think that there are more than a few people doing the same right now.
4e helped me learn exactly what I wanted from D&D. What I wanted just wasn't 4e.
RC