I really think this is the kind of appointment we should avoid. I worry about managers who have success at one single club over a short period of time, and to boot at a club where they have a special history or connection (as Simeone has with AM). It just doesn't transfer elsewhere that easily, as we've seen with AVB and Ramos.
It's also hard to say who exactly is responsible for the success in these instances - is it down to the current coach, or has someone left a good legacy there that the coach is just carrying on? Maybe he got lucky with a particularly good crop from the academy? Etc.
Of course, maybe Simeone is not one of those guys and is the real deal, but he jumped around clubs in Argentina like a good thing, and just has a slight whiff of flavour-of-the-month about him for me.
His mafia hitman schtick also bugs me.