Agreed- I haven't seen a games site that embraces streamers very well. Maybe a forum (similar to Recommened a Game) where let's-players can post their videos/ Youtube links of games they've found on the site would be an idea. They could use it to promote themselves and ask for game submissions based on what genres they prefer.
There is one games site that has a forum dedicated to let's plays, though, and it's a total mess. Every so often a desperate dev will flood every topic with their game, and you end up with long dead posts at the top, so there'd need to be a way around that problem.
From experience, watching how people play your game gives invaluable feedback and is also a nice reward for all the effort devs put in.