If he didn't win, the way he treats his players and coaches would be a major concern. No one cares though because he's an evil genius, and players still buy into his ways because they know he wins.
I do think the comparison between Cohen and Bianco is off too though. They are both hardasses, but they go about it differently. As jacksonreb says, Cohen does it more publicly and seems to get into it with umpires more often as well. He gets tossed more often. Bianco is tough too, but you don't see it as often from him in public or with the umpires. It's mostly within the private team setting with Bianco.
ETA: I like Cohen at MSU though, because he and Bianco seem to have some tension between them that I believe dates back to their playing days at MSU and LSU. They're both competitors, and I think their personal rivalry will drive both of them to work that much harder to try to out-perform the other. It's probably a good thing for both programs that they are facing off in-state as part of a rivalry. You can tell that they say the right things in the press, but you can also tell that they don't really have a relationship off the field, because I think they don't like each other.