Read this for starters, it is a good read.
Then there was Jack, the Knife.
Also, engineers and managers don't always have the political sense to make their forays into electoral politics and national government work. Cases in point: Herbert Hoover, the Great Engineer, and Jimmy Carter, who was at least on paper some kind of nuclear engineer. Their way of thinking just wasn't the kind of thinking that works well in the White House.
Maybe you could add MBAs G.W. Bush, and Mitt Romney to the list: not bad guys to have a beer with, maybe, but Bush wasn't on top of some important things, and Romney certainly wasn't very good at electioneering.
So Mulally may not deserve all of the automatic putdowns that are so easy to make up, but he wouldn't be my first choice for president by any means.