Meh.. I've been as hard as anyone on Carr for his play last season, but PFF actually rated him as the 24th best corner last year:
ProFootballFocus.com - By Position
The thing is he had the 3rd most snaps in the league among CBs, which is just ridiculous. He was probably exhausted most of the time he gave up big plays because we had a non-existent pass rush and our corners had to cover longer than they should. Being thrown towards 84 times and giving up 47 catches doesn't seem that bad when he has to cover for a longer duration than most corners in the league.
So for me at least, CB2 is not a perceived need anymore. Depth at CB certainly is, however.