I don't see how coming out with a game two and a half years after it was announced (and presumably longer since active design first began) is "rushing it."
The length of the playtest is completely irrelevent. I'm basing my concern on what we saw in the playtest combined with the information that they have "leaked" concerning what they are doing behind the scenes. While I, of course, can't see the full picture, I can make a few educated guesses based on the tone and content of L&L and Q&A articles, Mike Mearls tweets, etc. For instance:
1. Warlock and Sorcerer are probably
really close to finalized, but not there yet. And "finalized" doesn't necessarily mean every subclass they plan to put in the PHB is done--I consider that content more than concept.
2. The core rules are probably
really close to finalized. They have still been tweaking them the last we've heard. There is also a degree of uncertainty in the way rules tweaks are leaked. "What we're thinking right now..." may mean "We've got it completely decided, but we don't want to say that and start a flame war," but it may also mean, "we aren't quite sure yet." I think there is a combination of both of those running around on different rules.
3. I can confidently say that I have
no idea how much of the intended content (including subclasses, spells, feats) is completed. The problem with completion of content is that concept (meaning rules mechanics) needs to be set in stone before content is finalized. I'm actually optimistic that we will see a good amount of such content in the PHB. Probably not the 6-12 subclasses for each class that I'm hoping for, but I get the impression that we will at least get what is necessary for all the iconics (8 schools of wizardry, for instance).
4. I get the feeling that they are
well into the work on optional systems, such as realms management, tactical combat, etc, and I'd assume that they are at least making decisions about how much of it is going to make the PHB+DMG and how much of it will have to be held off for another book. On the other hand, I would be
quite surprised if they had finished the majority of the systems we've heard mentioned over the past 2 years.
5. I think they have
more or less decided on the default cosmology/setting/creature assumptions and how to integrate them with the rules. However, as we can see by the inclusion of a poll in the most recent Wandering Monsters, they are apparently still open to at least some input. Of course, I also get the feel that most of the polling
may be rhetorical at this point, or at least primarily intended on seeing if there are any unforeseen issues or overwhelming majority objection to specifics.
There is a common idea that is implied, if never outright stated, that I find odd - that Wizards of the Coast is completely unable to playtest on their own, as if they need to test everything with tens of thousands of D&D players. Don't folks realize that they've been playtesting in-house all along and that the in-house playtesting holds much more weight than your feedback and that of the other tens of thousands?
Part of the purpose of open playtesting - perhaps the biggest (but unstated) purpose - is to make fans feel like they are part of the process, that it is their (our) game. I'm not saying that they ignore external feedback, just that it is secondary to their own in-house work, and that feedback is of secondary importance to making us feel like we are part of the process.
I completely agree that playtesting isn't about "playtesting." We are a large focus group to make sure the game goes over well. I'm actually rather pleased with that level of involvement. I'd rather provide feedback on how to make D&D overall, rather than comment on how AC values are a point too high or low. I also agree that WotC are capable of taking care of the actual playtesting concerns in-house. What they aren't capable of taking care of in-house is taking the pulse of 175,000 players to find out that a lot of people don't want dragon eggs to hatch dragonborn because the dragons didn't please their gods. That's why it is to their advantage to
run stuff past us. Of course, they can't (and shouldn't) run everything past us. They have to make judgements, and I understand that.
I just have a really hard time feeling confident that they are going to be able to iron out all of that stuff in a couple of months so they can send it off to the printers. Given that we have people working there who have been there for previous edition releases (at least 4e), hopefully my concerns are uncalled for. But the way I see it, the last couple of months are a time period that should be reserved for adding content and editing, not finishing the rules and adding subsystems. Of course, now that I think of it, it's quite likely that if they did it that way corporate would tell them they don't need those last couple of months because they can always put out more content later, so perhaps it was an intentional good move to make sure nothing is finalized until right before the books head off to the presses so they can put in all the content we need in there. I do believe that the designers and developers love the game and want to make it the best it can be. I think they are trying to make it a game they want to play and they hope will meet the needs of as many players as possible. In short, I actually believe they are being honest with us. I'm not concerned with their intentions, just the uncertainty of the timing.