Something I’d find really handy is if I could upload routes, instead of simply downloading them - I pay for Strava premium and can also build routes in Garmin connect, so a route builder isn’t necessarily that useful to me. The benefits of seeing what roads a route would cover is really useful, though! At the moment I’m bound to creating a route in CityStrides.
You could even go a step further, maybe even Strava/Garmin connectivity to import all your routes across automatically (I have my Garmin set up to automatically sync my Strava routes so it’s definitely possible!).