I feel as if there are two separate arguments/issues here.
On the first - is Fleck an improvement over recent coaches? On that, the numbers -w/l and recruiting - all seem to indicate that Yes, Fleck is an improvement.
But - I feel the real question is how much of an improvement.
When Fleck was hired, a lot of people expressed optimism that Fleck could take the program to "the next level." Just posting a winning record and making to a Bowl Game was seen as the floor, not as the ceiling.
And - I would say - as of yet, Fleck has not reached "the next level," - at least when it comes to winning a division Championship or even a B1G championship.
Mason had some good teams, Kill/Claeys had some good teams - but they didn't win division titles or a conference championship. That is "the next level." Will Fleck get there? that remains to be seen. And - if he gets there once, is it sustainable or repeatable? that, only time will tell.
to be clear - I am NOT saying Fleck isn't a good coach. I am saying that, at this point, the jury is still out on whether he can take the program to "the next level" - assuming that "the next level" is an attainable goal for the program.