This is Tapscott's first time as an NBA head coach, but "he has plenty of front-office experience, including as president and chief operating officer of the Charlotte Bobcats and, before that, as vice president of player personnel and basketball operations for the Knicks in the 1990s." Grunfeld was running the Knicks at that time, which appears to be why the other assistant coaches were looked over.
Tapscott also followed Gary Williams as head coach of American University in 1982. When he was coaching under Williams, Tapscott "was in charge of the defense, and advocated a full-court, 94-foot game, a pressure defense and a fast-breaking offense," which is interesting to note because the Wizards do none of those things, especially the whole playing defense part.
The above link to the DC Sports Bog also includes the following quote from Tapscott:
"While I was attending Sidwell Friends, I used to come to AU to watch practice. The doors were always locked so I had to look through the cracks between the doors. I was an admirer of Kermit Washington and Tom Young's coaching and I hope to continue that legacy. The doors might not be locked now, but there will be someone watching who comes in."
It remains unclear at this time whether or not Tapscott plans to lock Oleksiy Pecherov out of practice.