Success is only half of the equation. Matta (health) and Miller (NCAA) have significant risk on being unable to coach in the next few years. I look at both as a stop gap, and would be really surprised if either is at their school for Year 4. As a Power 6 school I wouldn't hire a coach with so little possibility of long term success.
I think these hires are good for both Xavier and Butler. They are somewhat high risk/high reward, but that's O.K. for these schools. Butler, despite not being very good the last couple of years, has been a perennial NCAA Tournament team since they lost that heartbreaker to Florida in 2000 and came within a few inches on a halfcourt shot of winning a national championship. All of this in spite of constantly having their head coaches poached for better opportunities (Barry Collier, Thad Matta, Todd Lickliter, Brad Stevens, Chris Holtmann). They have a proven track record, at least up until LaVall Jordan, of being able to replace their head coach with somebody just as competent, so they have had that stability that SJU has only been able to dream about since Coach Carnesecca retired. Matta is only a risk because of his health and I imagine Butler is one of the few situations out there that he would have been willing to walk into anyway.
Xavier is in the exact same boat, except they have been a perennial NCAA Tournament team since the mid-80's and have displayed the same ability to replace their coaches (Pete Gillen, Skip Prosser, Sean Miller, Chris Mack) with somebody as good or better than the previous guy. Hell, they just fired Travis Steele DURING the NIT and they went on and won the whole thing. Schools like this can make these types of hires because if it blows up on them, or if the coach decides to take a job at a better program, there is confidence that they will find the right guy to keep the ship steady.
This does not apply to SJU. I can only speak for myself, I do not want a guy who's going to come in, baggage or no baggage, win for a season or two and then disappear into a better program. I have little confidence, based on the past 30 years of program history, that we would be able to replace him with the right guy. I want somebody who wants to be here for the long haul, who will build the program to the point where it's successful enough (my definition of successful is competing for an NCAA bid every single year) over a period of several years, that the whole house of cards isn't going to fall down once that coach moves on.