My understanding is that Rhule is an "executive" type coach. His position assistants coach up the players and his coordinators do the heavy lifting on gameday.
And that style can work just fine, if you know what you're doing when it comes to picking your staff. Rhule mostly kept his college guys in place. Likely on the belief that "football is football", which is roughly akin to thinking the guy at your local Y can teach basketball just as well as Phil Jackson.
I'm personally more comfortable with a guy who understands the X's and O's, the ins and outs, the flow of a game and such, and all at an expert professional level.
Clearly, that's not Rhule.