I have very, very mixed feelings about him. Mud yes, DSJ incomplete, and very inconsistent with Frank -- IMO completely mishandled. If nothing else Frank is a defensive player with the potential to be an extremely strong perhaps elite defender at the point. We saw him as a rookie (different coach) stop Wade and Harden both guys with a great handle when they tried to hot dog on him. We saw him block a dunk attempt by Ben Simmons.
Fizdale instead takes him off point and has him guard off ball 2s and 3s essentially neutralizing his greatest strength. Yes he can switch onto those, but he should be guarding the point. On top of that it's a mystery how Fizz had infinite patience with Knox, Trier et al on offense and almost encourages chucking but has no ability to develop a too pensive and hesitant offensively guard. It's not like Frank has a bad shot yet chucks in volume; quite the contrary
Regarding Mitch, his biggest developments seem attributable to Kerry Kittles who isn't even on the staff and to the last season acquisition of D. Jordan -- not to Fizz or staff
Lastly, he seemed to alienate not one, but two, foreign big men (Enes and KP) consistent with his experience with Gasol. My speculation is that KP got tired of all the damn talking and speeches and lack of passing and horrid defense and wanted out of town
I also think the FO was insecure and wanted more of a cheerleading, yes-man coach than a more independent and strong voice (e.g., Budenholzer)
Having said all of that, because I am a fan I hope I'm wrong and hope for the best, and that this coming season Fizz will unveil his heretofore secret offensive and defensive schemes. I know people frequently say it's all about the talent but I think that vastly underestimates the value of a coach. Kerr had the same team M. Jackson did and added something like 20 wins. Same too for Budenholzer (same team minus #2 pick Jabari Parker)
the sad fact is we were on the cusp of adding each of those coaches and missed out