Whilst I wouldn't mind seeing a plan for 1.1 and perhaps the next couple of releases after, I can understand why they won't release it. Not quite so much about other forum companies knowing what they plan - its pretty obvious what XF is planning to do - add more features inline with products it competes with, but more likely because there would be people saying 'why the &(&! is x in the plan and not y? Kier doesn't know what he's doing..." etc....
In other words, by not announcing it, they avoid people criticising them for their plans. Not that I blame XF at all for this, I'd do the same. After all, the number 1 rule in life is that you can't please everyone all of the time and someone would think that a Blog add on was more vital than custom profile fields (for example).
Its very much like moderating a forum, you can never win no matter what you do - someone is always pissed off at you! lol