If they could restructure his deal down where it reduced his cap hit to lower than it would be with a cut-and-re-sign, I'd rather they did that. I don't mind giving Cro, say, 4 years $20M. His health was a factor in his play this year, and given the increasingly better play from Milliner, Cromartie would likely be the #2 corner next year where he'd be a far better match for his assignment.
Let's not get crazy with moving on from players. We let Landry and Bell walk and we got significantly worse at the safety position. If you can keep talent in-house, you should if it's at a reasonable rate.
That said, if Rex is gone, maybe it's not even a conversation. Who knows how Cromartie would play under a different scheme or if he'd even be welcome here.