Flores has a lot more experience and seasoning not only calling a defense, but also he had a HC gig for a while too. He also happens to be one of the best DCs in this league, in my estimation at least. Might be a psycho with his staff, but he translates to the players.
Shula seems well balanced on the personality side, but he's in that learning curve as a young caller. So comparing him to vet DCs isn't really meaningful nor does it offer any real insight on the issue.
If I had to guess where Shula's knowledge is weakest it would be the secondary. He only had one season with our secondary, and it was our catastrophic title hangover season. DCs in the NFL all call the same shit. Now some like MacDonald are next level and develop streamlined reads and the like to find ways to get an edge, but overall it's about timing on your calls and to what extent you have the instincts to be in the right shit for the right situation. And also to what extent your players are prepared and mentally ready for what the other teams cook up for them.
That latter part is hard to evaluate when your corners are terrible. How do we know if he's any good at mentally preparing these boys when they have zero chance of executing some of the standard calls the DC is going to need to call. Williams in man coverage on Smith for example, with no safety help is a BBQ platter every snap.
That's a stupid take. Sounds like you're looking for a reason to go protest and stir up shit. Get the fuck out of here with that shit.
There's a small group that don't like the way Shula called it. Just like there was a small group who didn't like how Morris called it.