There are so many limits on meeting, practice time plus unlimited transfers that I think "coaching" is overrated. What Indiana did well was talent evaluation, and putting a system together that matched the players they were able to get. This has a lot to do with coaching retention, and system retention but coaches can't really coach-up guys longer than a year or so, and they have limited time with the kids anyway. This isn't like the old days when you wouldn't see a lineman for 4 years and then they would be an all-conference player.
The #1 pick in the NFL draft was purely mediocre at California, he steps on the field for Indiana, the same player, and is the Heisman winner. It is because his offensive line, running game, and short passing game were built for him, or he was built for them and they just found him and brought him in. Rhule has never had a cohesive offensive game-plan, he will have had three defensive systems in four years, and although his coaching turnover shows his willingness to change it also means nobody is connected or cohesive, and he himself lacks vision as a coach, while being unusually stubborn for a coach.