The risk of hiring a mad/strange/unstable/unusual "genius" is that dealing with the social aspects of their presence is not without its cost, even if there is a high probability they can generate the magic sauce. The risk of hiring a more well rounded set of team members is that you will end up with a pod of best friends who never end up generating the magic sauce.
Personally I favour the latter approach, I strongly believe that a more cohesive, well rounded team ends up being greater than the sum of the parts, and that quite often, a team containing a mad genius devolves into chaos.