A few things.
1st - I believe Rick Adelman was among the better coaches in the league in this article I read. IIRC he added a win or two per year.
2nd - Our lineup went from: Porter, Drexler, Kersey, Caldwell Jones/Mark Bryant and Duckworth in 88-89 to Porter, Drexler, Kersey, Buck Williams, Duckworth in 89-90. A huge improvement. Plus, we added Drazen Petrovic and Wayne Cooper in that 2nd year. The team gained a LOT of talent between that 1st year when he took over midseason and the 2nd year. And how did Adelman do that last half season after Schuler left? He went 14 and 21 before those guys got to the team. So...yeah...he actually didn't do shit until the team got better. Which is only natural.
You go on to mention that Adelman took 'talent challenged teams' and helped them win? Really? I guess I don't view our WC finals teams as talent challenged. Sacramento had Chris Webber, Hedo Turkoglu, Peja Stojakovic, Mike Bibby, Doug Christie's wife's husband, Vlade Divacs, Gerald Wallace, etc...Houston had Tracy McGrady, Yao Ming, Shane Battier and others. Those teams have a lot of talent. He was at Golden State for 2 years too remember. He won 66 games COMBINED. Why? Because his teams had no talent.
3rd - You mention Phil Jackson. As I said, the article implied that he was the best coach in the league and added a lot of wins. But you actually argue both sides of the fence with Jackson. "Are you going to tell me that Phil Jackson didn't lead the Lakers to championships after years of various coaches trying to get them to work together?" and "Jackson is a master at picking the team to coach." So I'm not really sure which you actually believe.
4th - Carlesimo averaged 46 wins per year for us over 3 years at a time when we lost the entire starting lineup from the WC Finals teams. He leaves for Golden State, which had VERY little talent. He lost a lot of games. It makes sense. Just like how Nate McMillan goes from 21 wins to 54 because the players on the team got better.
Anyway...take it or leave it. I know you don't like stats, you like gut feelings about things. That's cool, I get it. It doesn't matter one way or the other, since neither of us get to make the decision on whether or not we get a new coach. But in my opinion coaches really don't matter that much. All that most of them can do is fuck things up. For my money, I don't see McMillan fucking anything up in particular.