I maintain a list of features and bugs for the add-in.  I find both while using it during balloon flights and while developing features.  For the upcoming release, 37 features/bugs were implemented.  This includes a new algorithm for predicting flight paths using two wind data sets, better data management, consolidation of code, Tweeting from Flight Track, using a APRS-IS data feed to follow flights, and a new interface.
More bugs found and corrected this week in Flight file management (Flight New, Flight Open), and in flight path prediction.
I am targeting a mid-May release.