Obviously, they want "colorful" commentary for their MNF games. Of the guys who've been on that particular job, I'd take Mike Tirico and Dan Fouts as the best option but I'm not a Gruden-hater.
I think he's doing the smart thing though. He'll make a lot more money and have a lot easier time doing it by being in the booth. And, the legend of his coaching ability will remain in tact and probably even grow. It's win/win/win for him. Whether he's good, great, average or something else as a coach, Vince Lombardi back from the dead couldn't get the Raiders back to a Super Bowl any time soon so whatever coach goes there is facing real long odds.
And Chucky's job would come with unrealistic expectations. Anything less than a Super Bowl run would be considered a failure because of his previous success.
And, not that it'll ever happen for a variety of reasons, I'd put Kurt on color commentary on MNF if I was picking. He has the experience and I actually enjoy his commentary(i.e. agree with what he's saying much of the time).