If IU had landed Mack I would be concerned. Miller - not so much. Miller was the best IU could get and he seems like a pretty underwhelming hire to me. Schools like UNC, Kansas, Kentucky, and etc get proven coaches from power 5 conferences to come there. IU gets mid major coaches from obscure conferences.
That scenario would've been preferable, but my question is: which proven coach from a power 5 conference would've left their current position? You just named the most successful (well, K over Roy for ACC) from 3 of the 5 and none of them are leaving those schools. We know Izzo isn't leaving so that makes 4. I think that pretty much leaves Sean Miller and he has a good gig.
Miller was obviously at least 3rd behind Stevens and Donovan. I doubt Alford was ever even an option, especially given his comments and their timing before/after the tourney. I didn't want Mack and wouldn't be surprised if IU didn't show interest there either (a few years of his success were with teams led by Sampson commits). That pretty much leaves Miller, Holtmann, Marshall, and Bennett (yawn). And I think Miller was hired before Marshall, Mack, Alford, and Holtmann were out of the tourney anyway. De'ron Davis's comments about staying came pretty early in the tourney and I don't see a kid making that decision without knowing who his coach is; especially when the coach that was fired began recruiting him as a freshman.