Record Indoor Workouts!!! And other main stream sports... Integrate them into Fitness/Freshness.
You should be able to record indoor workouts. At least with a heart rate sensor. If you're on a device like a treadmill/rower/bike etc you could then manually put in distance. For other activities, like crossfit/squash/weights etc it would be a more challenging, but, still possible integration to get motion data from activity trackers. Heart rate data should be the base line though.
For everyone that does a lot of cross training in sports besides run/bike/swim, the fitness/freshness graph quickly becomes irrelevant. You're totally gassed from a hard week at the crossfit gym and f/f thinks you're fresh.
Strava, you need to make the jump from the run/bike/swim platform to the everything platform before the popular sports eat your lunch.