Not sure Steve Kerr should really be mentioned with the greats, yet. I love Pop. Of the contemporaries, I'd also mention Jerry Sloan and yes Phil Jackson who I think is great. I know he had all that talent, but here's the thing about winning. Winning makes players look great. Look at that Spurs roster. Leonard is a Playoff MVP winner. He's going to get a max contract. That's because he's a winner. On most other teams he'd be a marginal talent. Point being, you can look up and down those Phil Jackson teams and say they were stacked, but it's a chicken and the egg argument. Did they win because they had stacked teams or do they have stacked teams because they win?
Anyway, as for Thibs, me and Snero see eye to eye on this. We think he's great. Stan Van Gundy talked about player minutes a lot at a Sloan summit a few years ago and I completely agree with him.
https://www.youtube.com/watch?v=aZaCcg20TuYThe bit about players health is around the 32 minute mark, but it's worth watching the entire video. Really interesting stuff.
My opinion on coaching in general though? I don't think it makes much difference to be honest. I think the best thing coaches can do is manage players, and get them to listen. A team with a coach that the players don't listen to is done, but all these guys know how to coach. Every year the league fires a bunch of guys and calls them morons and incompetent. It's asinine. None of those coaches are morons, and none of them are incompetent. Not at that level. Some lose their team though, and a team that doesn't listen to their coach in a game with so many options on the court is toast.
Here's a write up that gives some perspective on the impact of coaches.
http://freakonomics.com/2013/05/30/a-former-nba-coach-argues-that-coaches-are-not-responsible-for-outcomes/I somewhat agree, although they take the analytics side and I think discredit coaching impact entirely, but I do think coaches are mostly blamed unfairly. I don't think Thibs is the reason Chicago hasn't done better. The real reason? LeBron James mostly. And injuries.