I agree that applied rationality is important, but I'm not sure that there needs to be another site for that to happen. This recent post, for example, seems like an example of exactly what the OP wants to see. Perhaps what should be done is creating an official "Applied Rationality" tag for all such posts and an easy way to filter them. That way, if a bad scenario happens where new readers more interested in politicized fighting than rationality are drawn to this site because there's a discussion on gun control, they can be easily quarantined. But if this site maintains its high signal/noise ratio, the community benefits from trying out its tools in action.