allow file uploads to be inside ZIP
Five years later and Strava still does not support what 99% of other websites can simply do - allow .tcx, .fit or .gpx to be inside a ZIP file.
Since sites like Garmin Connect export as ZIP it would save several steps.
No way this feature would take more than a day to implement and test.
(optionally you could also allow bulk upload of up to 25 files inside ZIP for importing)