Assuming the Colts land the first or second overall pick, some people feel that they should trade it off and build through the acquired picks/players to build a team to give Manning one or two more shots. My own opinion is that Polian should've been doing that over the last 2 to 3 years instead of wasting high draft picks on the likes of Jerry Hughes and Donald Brown.
My outlook is this -- if the Colts have the chance to take the guy who is arguably seen as the best college QB prospect since Manning, they pretty much have to take him and concentrate on adding the necessary supporting cast through FA and the rest of the draft. Unless something drastic happens, Manning will be back next year, the Colts will play a last place schedule, and more than likely, they're going to be a playoff team again and for the next few years. This is probably their only shot at getting a good replacement for Manning and if they don't, the Colts are probably sunk for several years after Manning retires.
Bill Polian and Caldwell are already on the verge of being run out of town and if they have a shot at Luck and don't take it, they are going to be sent packing.