As far as playing guys OOP, I have been told you lose some possession doing it, so I wouldn't put too many OOP...
But, that being said, I have a DMC who loves to play wing (8's & 7's at MR, 6's in his natural position!) So I think like Phil said, some guys that's how they work, and it seems to me it is usually an MC or DMC that can be the utility player and be put just about anywhere on the pitch in a pinch, and if you find they get those good ratings, leave them OOP.