My take - Fleck is the "backup QB" of coaching candidates. On virtually any FB team, the backup QB is the most popular guy on the team among the fans, because everyone is convinced that the backup QB would be better than the starter, if he was only given a chance.
That is Fleck IMHO. Anyone who does not like the current coach is convinced that Fleck would do a better job. And who knows - maybe he would. Or maybe he wouldn't. For every coach who has moved up from a mid-major to a major D1 school and succeeded, I could name a coach who tried to move up and didn't succeed.
There is no way to know for sure until you try.
So, here is the choice - stick with the known commodity in Claeys - or go with the unknown commodity in Fleck. With Claeys, you have a coach who has shown that he and his staff can produce a winning team, and IMHO they have shown a valuable commodity in D1 sports - the ability to respond to off-field issues, keep the team focused, and produce results.
With Fleck, who knows? He has shown success at a lower level, but that is no guarantee that he would succeed at this level. Faith may move mountains, but can it win football games? I guess I would rather stay with the proven commodity as opposed to gambling on the unknown commodity. But it's not my choice - it's Coyle and Kaler making the choice - which scares the bleep out of me.