I think it would be pretty helpful if you could extend the Goal system that you have in Sales / Bundles to allow for a single, pay-what-you-want game to be able to use it. 

My use case: I create some small games and I want to know if any have enough attention that it would be worth trying to improve it. I could use metrics like page views or downloads, but I think there's a bit of a gap between what people are willing to try or fart around in for free online vs. what people would actually be willing to buy. To that end, I could use the Goal system to say, "If this game gets $100, I would love to release a much more fully realized paid version."

Maybe I should feel comfortable charging even just a dollar, but I think that gap from free to $1 completely changes the expectations that people have for a game, to the point where these little game seedlings would need to be 2 or 3x better than they are. Especially when paying is voluntary, some small goal really could be a great way to gauge if you're onto something.