Fire the head coach - NO! If Peyton is healthy and they still are doing poorly...maybe, but this year the Colts did as well as many of the teams out there. You cannot go from a Peyton Manning to just anybody and have it work immediately.
Draft first round pick QB - Yes - as a back up to Peyton Manning. Peyton will not play forever (although I wish he could).
Cut Peyton Manning - are you people deaf, dumb, and blind? Let's find out how he is healed before you kick him to the curb - QBs like Peyton DO NOT COME ALONG EVERYDAY!!
I think the colts have had a ROUGH year, but I am hopeful for next year. Peyton Manning and the Colts have had a great season for many years in a row (not as many superbowl rings as they may like, but they are a world class organization). When the leader of a TEAM is displaced due to injury, especially one of Peyton's caliber and control of the game, his TEAM is going to flounder - they were beginning to rebound. Don't throw the baby out with the bathwater!