I think it's a joke for Spoelstra to be on top. It's a Coach of the Year award, not coach of the second half. That team started out terribly, and ultimately missed the playoffs because of their first 2.5 months. Good job turning the team around, but since there were no major acquisitions or injuries in the first half, shouldn't he get his fair share of the blame for being a bottom 3 team into mid-January?
I think the argument is Miami was decimated with injuries those first 2.5 months.
Dion Waiters, who turned out to be a very important piece to the Heat, missed 20 games from 11/28 until 1/4. Basically he played half of the first 40 games.
Also during the first half of the season, Dragic missed 8 games, Josh Richardson missed 10 games, and Justise Winslow only played 18 games all year.
I find that argument suspect. Waiters missed nearly half of the second half too. Dragic missing 8 games in the first half isn't nothing, but they went 11-30 during the first half, including 10-23 with Dragic. They were also better without Winslow (recordwise) than with him.
The Heat had some injuries this year, but they weren't decimated any more than the Celtics, Cavs, Raptors, or Bucks were. They were a fine story, but they didn't even make the playoffs. It's pretty unimpressive in my book. If they'd gone 30-11 in the first half, before having a few key injuries in the second half and finished 41-41, missing the playoffs, we'd call it one of the biggest collapses ever, and certainly not something that merits postseason coaching accolades.