I thought early on (pre-release of 4E) the schedule was FR, EB, then a new setting for 2010 that was designed for 4E. I know they've changed their mind a lot of times. It also might be part of their gateway toward gaining gamers (remember the timeline was D&D veterans first, then try to hit new guys) with a new setting that can be experienced on its own without an internet or table of veterans making things un-fun* for new players with their decades of knowledge from books and supplements.
It'd be kind of nice to see a fresh take on things without the board posts of "omg, they're totally breaking _________" and "they aren't changing the fundamental flaws.... I never liked _______ and this doesn't change that. Sorry wotc, you just lost my monies"
* = I understand this isn't always the case with majority of players, but seriously as someone unfamiliar with Forgotten Realms would you ever ever ever want to DM a group of people who are familiar? Even as a player it could be daunting to come up with a story and character concept only to find it's quite unbelieveable because remember in book X when...