I called going for a CB last week.
In the Patriots' scheme, it makes sense if you can't find the DE or OLB who fills your needs. There are two stud CBs in this draft, and pairing him with McCourty--especially when Belichick refuses to flip his defenders from one side of the field to the other--is a good idea.
I too would go with Carimi later in the first.
This might not be as arbitrary as it seems. Probably more often than people realize, guys who are good at LCB aren't so much at RCB and vice versa.