Not saying he's moved to the top of my list, but I could get on board with McCown as HC. I was OK with Culley for one more year or two and McCown would not be any worse and would likely be an upgrade.
From what I've heard, McCown has high reviews for his ability to work with people. So for the team management responsibilities of a HC he would likely be as capable as any young hire. And as a 20 yr qb in the NFL, in multiple schemes, and although unproven, he very well could have a high ceiling in the X's and O's of an offense. For game management, there is not any reason to believe he would do any worse than any of the other young candidates being mentioned. He definitely may need help on the defensive side of the ball, but the Texans have Lovie.
With a capable OC, McCown could be a solid risk if the Texans were to go forward with youth. Two other young, inexperienced names being mentioned are Jarod Mayo and DeMeco Ryans, both on the defensive side of the ball. I've said I'd prefer a HC with an offensive background. McCown just could be the one and I'd be OK with that.