If you look at the Timberwolves stretch, Flip had Kevin Garnett in his prime. As we see from his results after he was dealt to Boston, a Kevin Garnett in his prime should have been able to lead a team to the conference finals on a regular basis (and maybe even the title). Flip reached the second round of the playoffs....once.
Flip then went to Detroit where he took over a team one year removed from an NBA title and he.....never reached the NBA finals. Included in this stretch was a game where Flip allowed LeBron James to score something like 25 consecutive points in a playoff game. That cannot happen, ever. If you have to put 3 guys on LeBron and let 2 Cavs float wide open, you just cannot as a coach allow that level of dominance by one guy to continue.
Flip then went to the Wiz and........he has sucked.
So, based upon that record, what do we know about Flip? Has he ever led a team to a record or playoff performance that was unexpectedly good? No. Has he won without a start player? No. Has he developed young talent? I guess maybe Garnett, but after that, nope.
You wonder if this was just a case of Kevin Garnett being such a dominant player that his coach's general averageness/mediocrity was never exposed. And when he starts a year 2-15 and gets replaced by Randy Wittman, you wonder even more.