Knowing and admitting your failings doesn't mean you can change or overcome them. How people can't see that is beyond me - it's possible, but it's not always reality. McDaniels could or he couldn't be a good head coach the second time around, lots of guys on either side of that coin not just in coaching, but in any profession. I happen to think talent rises to the top pretty quickly and distinguishes itself from the others. He's certainly done that on a OC front, but not as a HC. I think the combination of him and Reese would be a boon for the NFC east opponents of the Giants. Reese hasn't exactly proved to be a talent wiz so if McDaniel got the gig and he could put his learning into practice the smartest voice in the room would be Reese - jesus. But as MAU stated he doesn't seem to fit the mold of Giants coach.
I compare him with Charlie Weiss because I know people on Charlie's staff at his various college coaching stops and he was and is an ass and he does think he's the smartest guy in the room and Josh by his own admission fell into the "smartest guy in the room" category as he admitted he didn't listen to anyone. Again not as abrasive as Charlie, but you'd have to try really hard to be that abrasive.
I'm not saying you had an anti-Patriots bias at all, more of an anti-McDaniels one. My comment was intended to imply that he burned your Broncos and that probably still sticks in your craw.
Nor am I saying McDaniels will be guaranteed good, but you are automatically lumping him in the Weiss category, and disregarding the other end of the spectrum. BB has many of the same qualities you mentioned. And as noted, he was a failure at Cleveland and learned from many of the errors of his ways. The better coaches learn how to adapt. BB did it. Coughlin did it. Carroll did it. There's nothing saying that McDaniels can't do the same, other than your desire to paint him like Charlie Weiss.
A really hard problem for 'smartest guy in the room' types is to admit that very fact. If McDaniels is capable of recognizing that in himself, then it's reasonable to assume he can probably address it. The fact that he said he was "humbled" many times, says a lot to me. He's going to need help, and he realizes it.
Do I think JM is going to be BB? Of course not, nobody is. And ultimately, if JM doesn't have a legit quarterback (not Brady level, but good), he'll probably fail like every other coach in the league. Just the way it goes.
As far as the Giants go, no coach will fix that situation, unless Reese magically fixes his own problems. I'm not betting he will. You can't win consistently without players. People say Coughlin cost the Giants a whole bunch of games, but the reality is that he might be one of the big reasons a less than cast of characters was in those situations in the first place. Looks like we'll find out.