Anton, I'm going to make sure that in the next release it'll be possible to add your own data to it quite easily. Maybe not all types of data to start with, but certainly important bits (airfields, runways). Terrain drawing is done dynamically, there are no images. There's a page up on the SkyAngel site about the terrain data we use if you're interested.
mad_jock, searching for a waypoint by its ident is as easy as typing in uppercase in the waypoint finder window. Ctrl-F, EGHA, takes you to Compton Abbas. Radio aids and reporting points work the same way.
tlowther, we should definitely include waypoint details in the tooltip; good idea.
To dog-leg a route: just click on an existing route segment to select it, then click a waypoint to insert that waypoint in the route segment. You can ctrl-click to create a new one and select that. Is this too difficult? Are you expecting to be able to just drag a route on to a new waypoint rather than clicking twice?
yakker, the next release (which will be next week) will keep your user waypoints from one session to the next, and it'll also allow you to have your own personal database so you can add to the airfield database included with it. See above re doglegging a route, I'm interested in this because a lot of people seem to be having problems with it.