When Wotc says it's going to include something or even suggest it's looking at including something in a product, and then doesn't include it, people get upset. Not "you killed my childhood" upset, but unhappy enough to talk about how WotC "lied" to them and suggest the product is not worthy buying.
I've seen this before. This is one of the big reasons we authors often don't say much about our books until they're in print. Even if the book is written, developed and edited, something may get cut at the last moment for all sorts of reasons. I've had whole sections cut from books days before it gets printed because layout didn't quite manage to squeeze it in, or another book turned out to be a better match for the information, or a license changed, or a late playtest report discovered a serious problem, or a piece of art failed to arrive in useable condition, or someone came up with a better idea at the last moment, or because it turned out to overlap or contradict information from another book in production I never got to see. So I try not to talk about what's going to be in any book until I at least have a preview.
Now, the DI isn't a book, but there are certainly lots and lots of reasons why anything in it might change in the half-year between now and when it goes online. Even if WotC is waaay ahead of schedule developing it, they might change their mind about any one factor. So if they give you any solid details at all, they're forcing themselves to either stick with an idea even if they think of something better or risk further disappointment and anger by taking away something they mention then change.
Because this isn't a book, there just isn't as pressing a need for lead-time. You don't need to know if you're going to pay for this now. Retailers don't need to decide to carry it. WotC doesn't need to convince the book trade to pre-order a few thousand. In fact, WotC doesn't need to "print" them at all, so they have even more time to get it ready than Paizo does Pathfinder. Ultimately, WotC only needs to have everything in place 1 hour before their go-live deadline.
Paizo, however, does need all that lead time. In fact, they needed it before THIS WEEK so they could present what they needed at the GAMA Trade Show. They need to be able to explain what Pathfinder is, and why a retailer might want it. They need to convince people to use leftover subscription money to buy Pathfinder, and find out how many the book trade is going to want. They need time to deal with customers who are losing something Paizo has been selling them. Paizo -has- to be ready starting now. From a practical standpoint, WotC just doesn't.
WotC extended the license to Paizo would be able to finish their existing adventure path. Obviously Paizo has known about this for some time, but no one is upset they waited until the last possible moment to tell us -- the week before GAMA. The fact Paizo had a lot of details isn't a sign of corporate incompetence or some hidden agenda on WotC's part. It's a sign WotC wanted to let Paizo do everything they needed to for this transition to go easily for Paizo, even though WotC isn't ready to reveal details yet. The chance of two companies having all their ducks in a row on two separate projects at the same time is really low. So WotC let the announcement go out now, when Paizo needed it.
If people want WotC to have not said anything until they were ready to give us details, they're likely wishing WotC had made life very difficult for Paizo. I, for one, am glad they didn't.
