I think this is a good idea and one I don't think I've ever seen implemented anywhere yet. The problem is that there is no real standard for id3 genres and often peoples libraries are littered with a hundred different types of genre tags that might mean the same thing - end result would be spotty unless the user really puts a lot of effort manually cleaning up their tags.
One of the things missing that would make Poweramp perfect for my use would be for it to be an MPD client. I serve out all of my music on my network with an MPD server. It would be awesome if I could connect to the server and stream everything to Poweramp rather than relying on a separate inferior music player just for this. Primarily interested in streaming but it would be a nice bonus if it also allows you to change the MPD output to wherever.