Indeed we plan to support high qualities than 480p in the future. We are just going to slowly ramp it up depending on our ressources, stability, and the number of users on the website.
At the moment getting rewarded on DTube with some quality video is pretty easy because the website is new and competition is low. Just give it a few months ;)
It's not a complaint, merely an observation. Eventually having 720p would be great as that is the lowest resolution my editor will convert to from 4K, this eliminates one step in the process. Greetings!