This seems on the surface a fantastic idea - in my opinion. I say "on the surface" because I'm really tired just now, and I need to check this out further - but you have explained it in such a clear and lucid way that even my exhausted brain can grasp it!
I don't really understand why so many people are getting worked up about the "ethics" of bidbots. I have used them in the past, but I never use them now - not because I see them as "unethical" but because I think bidbots are a mug's game. In general. I hate the way that the Trending page is full of bidbotted sh*tposts, but Steemit isn't a religious organisation - it's an online community, and I think it's up to us as a community to handle these things. And a bot that favours quality posts seems like a great thing to me.