The issue a lot of people are forgetting is that these selective betas are giving you the best the game has to offer for the most part.
Go play ANY gae out there from start to around level 20. I dont care if its a game youre bored to tears of. Those first few levels and areas fly by and it looks awesome. Not until you start getting into the meat of it (which no one has seen in regards to ESo yet) do you really see what the game is like.
THAT I think is one of the main reasons why the NDA is up. Its easy to drop the NDA for the press when theyre seeing everything a million other people can see for themselves. What a lot of folks want to here are the people who got past that beginning area.
This to me looks like AOC all over again. Let people see the first zone(s) and keep the NDA up late, brag about how awesome the PvP is going to be and hope people are preoccupied enough to see the glaring shortcomings in the PvE.
All the fans might love to see the NDA drop so they can give their opinions (just like everyoen else can) but what Zenimax doesnt want to see are the reviews and previews of the few hundred people who have seen past a level 15 zone.