A very huuuuge advance with SD would be to compile and fly IFR clearences in realtime. This means having the possibility to fly on the Ipad the SID, STAR and APP with a small Flight Director (GPS based) beside having the track to follow (and the climb profile) on the map and virtual radar.
In terms of selling the product this could be done by buying a single airport IFR charts or a single region with the option to subscribe a 1 year update of all the charts every 28 days.
What you guys think ?