Mark Jacobs notoriously talked a big game about how keeping a beta NDA up within a month of the product's launch is a vote of non-confidence in the product, only to keep Warhammer's NDA up until four weeks before the launch date. Today, four weeks is actually a comparatively generous amount of advance time for the closed beta NDA to be released. (Exception - Blizzard is still holding closed testing that remains in progress but free from an NDA for multiple months. Perhaps that's a quirk to their glacial development cycle?)
Instead, we see scheduled "beta events" which carefully manage what can be accessed by potential customers - or sometimes actual customers, since access to even these staged previews increasingly requires a non-refundable pre-purchase. From a marketing standpoint, these events are no doubt a huge success. Besides driving pre-sales, the limited and staged access fertilizes the grassroots, such that all the blogs are talking about the same parts of the same game at the same time for one weekend only. Meanwhile, all of the information that a customer would need to make an informed purchasing decision about the product remains sealed away for as long as possible.
I get what people are saying when they complain of feeling nigh persecuted for being overly enthusiastic about the upcoming hyped product. As gamers, their anticipation is perfectly natural. I think what we're seeing in this backlash is misplaced frustration on the part of each gamer that's also a consumer - trying to piece together enough information to tell whether to invest their time and money in a new product. As consumers, we're put in a position where it is all too easy to make the wrong call, whether it's purchasing an unfinished product, or, in the rare and fortunate case of MMOGC et al, in writing it off too soon.