The major features that we are putting into X-Plane 10 were decided, for the most part, a long time ago. Those who we met in France two years ago won't be surprised by the major items on the list: weather, ATC, airports, and new scenery, new shaders. For that kind of major feature work, we have to start an initiative very early on. Heck - global sun shadows (which I believe we will ship in v10, God willing) were in the works before version 9.0 shipped - it took that long to get an implementation that was useful! (In fact, the v9.0 version was not released because the quality was bad, which is why I am always nervous about announcing features in advance; it ain't over until it's over.)
So while it's exciting to see so many people discussing X-Plane 10, realistically if a feature is a "big" feature and we haven't started it now, it's not going into 10.0. That train left the station over a year ago.
There have also been two complicating factors that have cropped up during the X-Plane 9 run:
- Microsoft closed ACES, which definitely changes what we want our next major release to look like.
- The iPhone came along - until the first iPhone release, we had no idea that it would be such a big product.
So bear with us - a lot of what I see are good ideas that we will get to soon, even if they don't go in the initial roll-out.