Tim,
regarding the NOTAMs I think there will be a need, unless the software can be made to automatically download NOTAMs for every part of the world (as I think it does for the UK at the moment?).
We currently have
eight pages of QOBCEs (obstacles) in the NOTAMS. With a few OBST LIGHTS U/S it makes for interesting night flying. I don't know if we're ahead of the times regarding the wind power plants, but I'm sure that's the way it will be all over the place eventually.
Add a few temporary restricted areas for military exercises now and then and you're really certain to eventually miss something.
How about letting the user choose to either add to existing manually entered NOTAMs, or to just wipe all NOTAMS (or just manually added NOTAMs) when entering new ones?