I think the last 5 years or so have vindicated him somewhat. Everyone in Denver lost their minds because he couldn't make it work with Brandon Marshall and Jay Cutler, who have since had locker room issues everywhere they've went, and in Cutler's case hasn't turned out to be anywhere near as good as his supporters thought he'd be. Cutler good enough to be worth keeping around if he won't buy in, McDaniels just realized that a couple years before everyone else.
Marshall, OTOH, is a genuine asset, but at the time he hadn't yet got around to treating his borderline personality disorder, so it's hard to fault anyone else for him being essentially crazy.