I do think this season was much more than just about losing Peyton. I don't feel like reviewing every draft the Colts have had the past few years, so I don't want to say they have been drafting poorly, but there are certainly some odd decisions that were made recently.
If I were them, I would take Andrew Luck with the first pick. Then I would wait and see what happens thereafter. If St. Louis and Minnesota hold their ground, you know they aren't going after QBs. So as long as they don't trade down, I dangle Luck in front of Cleveland for a king's ransom and take RG3 with their pick. If they get Luck and keep Manning, one plays. But RG3 is such a contrasting player to those two, that he can learn behind Peyton and still bring dynamic playmaking ability to the field in certain packages. So you get better immediately, but also build for the future behind Griffin's immense ceiling and the added picks you receive in the trade with Cleveland.