What's the name of the app? Basically I use Strava, but always willing to look at other apps.

The one I'd like to see would be a collaboration between some hardware people and software people. Get the hardware people to make a pinion type gearbox or a Rohloff type hub, with gears as low as those two have, priced at $400-$500.

Then have an app that does all the GPS stuff of a strava, but doubles as the brains of an automatic transmission, docked in a handlebar cradle including cable pulling servo motors. Have the cable unpluggable so it can be inserted into a shifter for manual control.

Then you could tell your app what you're doing and have it give you cadence feedback etc while it shifts gears optimally for the path/trail you're on.