Now that Wizards has finally provided a firm date (May 24th) for the release of the DnDNext playtest some official details have started to trickle out (here). Mostly the designers at Wizards are trying to set some expectations: the playtest will include a very basic rule set with a minimal set of races and classes, although the playtest material will include pre-generated characters. I am also assuming Wizards will provide some avenue for actually providing the feedback they are looking for.
The playtest has been held at a few conventions already, and although not much information was forthcoming because of the NDA restrictions one of the things that was reported was that the playtest versions were indeed being tweaked and updated between the different playtests. In fact the article mentioned that Wizards anticipates updates to be released on a regular basis ("brisk pace" was the term used at the link above). This should make for an interesting summer.
Hoax Update: In a previous post I had noted that Barnes and Noble had links pointing to new releases of the DnD 3.5 PHB and DMG, followed by update that the releases were just a hoax. After I published that a little bird flew up to my ear and told me that they really were going to be released after all. So I think I can say with some certainty that the mysterious DnD 3.5 books either will, or will not, be available some time later this year.
Now here's my grumble. I really don't care if they are going to be available or not. But they either are going to be available, or they aren't. If they are, then that required a business decision to start the process, some amount of effort to get them ready for release, and dates and commitments from a printer to actually get them onto the shelves at a designated date. On more than one occasion a sharp eyed DnD'er has spotted new release material (including a proposed release date) on various book seller websites before Wizards ever makes any kind of official announcement. I suppose Wizards could have gotten caught in a bad spot when the re-release of the 1st Edition books got pushed back because of publishing issues in China, but for this they still haven't officially said "Yes," but they have not said "No" either.