The approach they've taken with allowing certain high-profile bloggers, journalists, and visitors to a single con to playtest something and then talk about it "under NDA" is part of the process that I think is flawed.
It leads, for example, for gamers hungry for information about D&D Next to examine every dribble of information ("aha! there are DWARVES in D&D Next, we know that much!") as a potential clue to the system.
It would probably be better if they simply said either "talk about whatever you like, we're going to change it 137 times in the next week anyway" (i.e., no NDA) or had said simply said "don't talk about."
Instead there's this somewhat halfassed approached whereby many people who try to follow the topic are left confused as to whether stirges do Con damage that takes weeks to heal, or whether there's something odd about healing in general (as a few playtesters have reported), or if boss fights in 5e really take 5 minutes, or whatever.
Their releases of information on what they want to put in the system, from their seminars, have been okay -- but WotC is still being pretty deliberately tight-lipped about nearly everything, from the vague L&L columns on down. That doesn't seem like a great idea when you're (maybe?) 18 months out from a release; maybe they should be holding back less instead of dropping tantalizing clues, if they're not ready to even let anyone know when the "open playtest" is really going to be open? (So far it's all been an under-NDA playtest and not open.)
So yeah, I think WotC is handling this poorly in a way that isn't productive for them (putting aside whether people are speculating irresponsibly for a minute) and I think they could handle it better. It was probably premature to do a well-advertised playtest at this time, for example.
The fact that Dave's and Mike's posts ignited minor kerfluffles is proof there's a problem -- and yeah, part of the "blame" goes on those people who make assumptions.
(Which is why I thought it was appropriate to start this thread here and point out that faulty assumptions ARE being made when we interpret DM fluff decisions from DDXP reports as being something based in 5e rules.)