I think the positive on both is they've adapted to the talent they were given.
BF has certainly adopted a lot of what TB likes into the offense. If he didn't and they kept chucking it like that fool Ariens wanted they never would have won the SB. The ability to read the defense presnap with motion and slow down a pass rush like KC with the short passing game being just two examples.
BD with Allen as his QB has morphed his play calling to be different than any other place he's been. Allen has also developed as a pocket passer beyond where I thought he would ever get. He's never going to get to the Brady or Manning level of reading and manipulating but with his skill set I don't think he has to.
Now does that mean either will be a successful HC? Hell no. We've seen lots of geniuses on both sides of the ball not be able to manage an entire team. It's like going from a department head to a CxO position. That doesn't mean they don't deserve a shot. One of the first signs of if they have what it takes will be turning down one of the perpetually disfunctional franchises, IE Jets, Jags and Lions. I don't think any of the coaches considered top tier could be successful in these hell holes nevermind a first time HC.
For Dabol, I wonder about his relationship with Casario. While I don't think Culley has done a bad job given what he's been handed to work with, Dabol has that Patriots experience coupled with having helped develop Allen.