It would be cool if you could manually add landmarks to the maps. For example, the names of peaks, towns, bodies of water, etc. It would be amazing if this could be pulled in automatically, but I don't know if there's a good public source of landmark data.

It would also be cool if you could automatically link your media to the GPS track, like photos and journal entries. They could be assigned to the correct spot in the track via their timestamp or geolocation data.