That's a tough one! I've considered creating a non-gamified learning app based on spaced repetition and active recall - think Anki flash cards but on steroids :D

The reason why I haven't done it yet is because I never have the time, but if you do then I for one would love an app like that.

There's a lot of talk about today's market, but I think doing something and sticking at it will attract the right attention