I wish transmission supported mutable torrents (BEP46). It would allow completely re-thinking distribution: grab a torrent of your favorite distribution, and have it auto-update to the latest version.
Or grab a "super-torrent" that lists isos for all known distributions, select the ones you're interested in, and let it update... Of course, that can be used for file-sharing repositories too.
Maybe transmission is not interactive enough for such a use-case (you'd have to ask the user what they want to do when the torrent mutates, and possibly add simple scripting interfaces for more complex heuristics).