N+1 format: Let the number of teams in the tourney equal the number of losses of the regular-season champion plus one.
Champion byes: The regular-season champion gets a first-round bye whenever there is an odd number of teams eligible.
Champion venue: The tournament is held on the home court of the regular-season champion.
This setup generates the most interest during the regular season in both the leader's games and the potential tourney entrants' games back in the pack (unlike this year you couldn't know for sure which games "didn't matter" at the end because the leader might drop another one). It also gives that nice "everybody rooting against the leader" dynamic where those who pull upsets become league-wide heroes for a day. It rewards and protects the regular-season champion for its grueling round-robin success, but it scales the level of protection to the degree of their success.