I generally like your stuff, but I disagree with a lot here.
Xavier plays in a relatively weak conference. I don't think they would have won the Big Ten, for example, at any point in the past five years. And this year they were an #11 seed. They've won some tourney games, but they've never really been a contender to win it all or anything under Mack. So, when projecting what he could do in the Big Ten, it's exactly that - a projection. I wouldn't say he's done any better at Xavier, for example, than either Matta or Miller, and he hasn't done any better there than JB did at WVU or heck, than Crean did at Marquette.
I like what he's done, sure. On the other hand, Reynolds has character issues and Sumner was a guy we just didn't recruit. Also, it's just flat inaccurate to say he beat us out for Blueitt. We moved on from Blueitt when he rescheduled a visit to go to UCLA instead, he committed there, he decommitted, and we took a pass the second time around before he wound up at Xavier.
Mack is, actually, a worse recruiter than Amaker was at Seton Hall. Everyone thinks hiring the young, exciting, "fresh" coach is going to lead to great recruiting. I don't think it will. To me, Collins would be a far better fit (and would probably be successful) because he would understand the culture, coming from both Duke as a player and NW as a coach. Plus, he probably knows more about coaching than Mack, given that Doug is his dad.
If you give Collins a Ryan and Nance, he's probably got enough talent to finish in the top 4 in the conference. NW was a nice story this year, but there were times (most notably against MSU, and against Wisconsin in the BTT) where they didn't look like they were at the same level as some of the better Big Ten teams. Sure, they beat us by two in Evanston, but you play that game in Ann Arbor and I think we win by 10. They're an up and coming program to be sure, but I'd be shocked if they are ever a Final Four contender. Time will tell - unless of course Collins bolts first.