@OP I don't disagree with anything that you are saying but we will have to wait and see. Cromartie from a physical standpoint is everything Rex craves in a CB; now if they can turn him into the shutdown CB to play opposite of Revis than that would be great but only time will tell. I definitely agree with your assessment that the move from Rhodes to Poole was a downgrade but we still have the draft next month and there is nothing that says the Jets don't upgrade the secondary (CB & S) in the draft.
On LT, he is not the feature back (as was TJ). I'm still not convinced that TJ wasn't insisting for an open competition for the starting RB position which may have escalated his departure (this is exactly what he did in Chicago when they wanted him to take a backseat to Benson). LT will be a backup and provides a different dimension to our offense that TJ did not (a true HB with the ability to lineup wide). Starter vs Starter TJ may have been the better option but Backup vs Backup I think LT is the better option because of his versatility.
We still have the draft and the rest of the offseason so evaluating a roster at this point is way premature. Who knows we still may sign Strickland and Sheppard to low end deals for depth when it's all said and done (now I don't think anyone would say adding Cromartie and keeping Lito would be a downgrade).