I think it would be really useful to have two new sorting criteria for Radarr:
1) Sort by file size. This would make it much simpler to free up space directly from the app by flagging the 50Gb movies that I'll never watch again. Also it might help identify lower-quality movies that could be manually upgraded.
2) Sort by resolution. I think using horizontal resolution only would be best - that way wonky letterbox formats like 1920x800 wouldn't screw things up. I would use this mainly to flag movies that I'd like to upgrade.