I know zero about Carey (who does he coach?), but I like your analysis. Golden would be as very attractive hire, but DeRuyter is intriguing....that Bo knows defense. Then I would look at 2012 and 2013 and think, in a puzzled sort of way, that the guy has just lost his way somehow.
This business of hiring new coaches is pretty tricky. You look around and try to find someone with a proven track record of success who would consider moving for the right job. Or you look for that "can't miss" coordinator who is ready to move up. DeRuyter is enjoying success now in his current gig. If he keeps it up, someone will give him a shot at the next level up. If he is interested in moving, he'll move up quickly. I'd certainly be interested in looking more closely at him.
Look at the top 25 and try to sort out which coaches on that list of teams might be available and interested:
Saban......no
Helfrich.....no
Fisher.......no
Meyer......no
Shaw.......no
Briles.......not likely to leave the state of Texas. May get Longhorns job.
Golden.....okay, maybe. You'd want to check his interest level
Dabo Swinney......Unlikely. Would you want him?
Pinkel.......seriously?
Stoops.....nope
Malzahn.....no way, in his dream job currently.
Sumlin.......No. ATM has more money, better access to recruits and plays in a better conference.
Miles........no
Spurrier......needs year round golf access
Kingsbury.....alma mater/dream job
DeRuyter........highest ranked team whose coach could reasonably be expected to be interested.
Carey.........doing well, but just became head coach last December. Would be interested, though....
Gundy........no, in dream job currently
Strong.....interesting possibility. Most think he's looking for SEC job
Mora......not going to trade LA for Lincoln
Hoke.......no
Dantonio.....Bo with heart disease
George O'Leary........no
Anderson......just moved
Mike Kelly......no
In looking for a current head coach at the FBS level who is enjoying success but might want to move, DeRuyter seemed to me to be as good a candidate as anyone.
Oddly enough, I'm not even sure any of the bolded choices are any better than Bo Pelini. That's why firing a coach can be tricky business. You might think you are getting an upgrade, then find out that you didn't. Who do you like?
My first choice would be for Bo to somehow figure this thing out, get to 8-10 wins and somehow figure out how to get better. I hate coaching changes.
And I agree with the hope for Bo to right the ship. It's just getting hard to believe he can.