I think Peterson is faster than Rolle ever was but it's certainly possible he could be moved to S at some point. It doesn't bother me because if people hadn't noticed, we WILL have a need at S. Wilson is a liability in coverage, I like Rhodes a lot but I would not have an issue with drafting a kid who's a great football player who might move to S down the line a bit.
My issue with Rolle was always we desperately needed a CB, and took the one that was clearly going to have issues playing CB and then it took us years to realize he was a S.