Interesting, not long ago I was in search of such a site and thought about building my own. Eventually I found this site (basically the same as your site from what I can deduce), which I've found isn't great (mostly because of lack of participation though): http://www.convinceme.net/. How will you distinguish yourself?
Seems to be a good start though. I understand it's a MVP, but with the design of the site currently I don't know where my eyes are supposed to go on the debate page. What's the main focus? Where should it be?