Uploading run workouts into TrainerRoad directly is definitely on our roadmap! The only problem with incorporating compatibility with a device like an Assault Air Runner to measure running output is that it would take a LOT of resources for us to do so (or for most manufacturers controlled by 3rf party), for a device that is ultimately pretty scarcely available to most people. 
This is why instead, device compatibility to import run/swim workouts with more commonly used and accessible devices is on our roadmap!
I think a Feature Request for a running-specific side of TrainerRoad would make more sense when a way to measure and analyze running output becomes more accessible. Lets hope these continue to develop! 