David,
Excellent question.  We do not publish specific features with dates; I've been developing software long enough to understand that although sales folks love doing this, in the long run it can lead to busted expectations.  But I expect our iFly owners will attest that we're doing a pretty good job of continuing to imporve the iFly, and doing so at a very rapid pace.
This is our process:  We determine the best features based on user feedback and development level-of-effort.  The feature lists becomes a hybrid of the most important features for our users balanced by development costs.  Then we build the new version, and perform QC until we're satisfied with the quality.  Then I release the product to beta and let real users test the new release.  When the beta testers find bugs or make additional simple suggestions, we implement those and re-release to beta.  When the bug fixes stop coming in, we release to production.  The entire process typically takes 4 months from start to finish for a major release.  
I will announce the contents of a release before it goes to beta.  If I do so sooner there is a risk a feature get's pulled last minute, and I really don't want to have to explain that.  For example, terrain was actually internally planned for the version 5 release - but at the last minute we discovered issues with our data and had to scrap that feature. 
I am happy to give you our high level plans for a release, but I always caveat this with a caution not to take this to the bank...plans can change.  We're shooting for a summer release of our version 6 software.  The major intended features for this are ADS-B weather, terrain, and geo-referenced approach plates.  There will be some other smaller features such as an improved timer and checklists.  Because we have 3 huge features slated there is a good chance one of them will slip.  And based on user feedback I think ADS-B and Geo-ref plates are more important, so if we need to slip something it will be terrain (again).
I hope that adequately explains our philosophy and where we are today.  Version 7 is still in the white-board phase.  Some things being thrown about include portrait mode, WAC charts, HSI and other simulated analog instruments. 
Thanks!
Walter