To me the thing with Rizzi is that, although I didn't like him throwing a hissy fit at Hayball while others messed up on the same play and he didn't do that to other guys making mistakes, there is more than one way to lead and maybe his way works. But, even if he is a good leader, he showed a lack of knowledge of the rules on more than one occasion and even argued with the refs when he was just wrong about the rules. I just don't think you should be a head coach in the NFL if you don't know the ins and outs of all of the rules. And the fact that he didn't tells me that he's not ready to be a HC.
And that ignores that it's really hard to have to keep both a good OC and a good DC because your HC is a special teams guy. It can work, Harbaugh, but it's a higher degree of difficulty.