Personally, I think the NBA would work very well using the relegation/promotion model. As it is, the Eastern Conference is a model of mediocrity, with only two teams that would've even made the playoffs in the Western Conference. The way my NBA Promotion/Relegation model would work is as follows:
Upper Division (UD) = 14 teams
Lower Division (LD) = 16 teams
1st place LD team gets a bye to the finals of the 7-round "Promotion Tournament"
2nd place LD team gets a bye to the semifinals.
3rd-4th place LD teams get a bye to the 4th round.
5th-8th place LD teams get a bye to the 2nd round.
9th-16 place LD teams play in the first round.
Rounds 1-5 are knockout (NCAA tournament style). Semifinals are best of 3. Finals are best of 5. Top 3 finishers earn promotion. Tournament winner gets the first pick in the draft.
Bottom four teams play in a standard-format playoff. (11 versus 14; 12 versus 13; winners play each other in the finals)
First round is best of 5. Finals are best of 7. Winner of this tournament avoids relegation, and gets the second pick in the draft.
NBA CHAMPIONSHIP TOURNAMENT
1st-2nd place UD teams get a bye to the semifinals of the 5-round tournament
3rd-4th place UD teams get a bye to the quarterfinals (3rd round).
5th-6th place UD teams get a bye to the 2nd round.
7th-10th place UD teams play for the last two spots in the 2nd round.
Rounds 1 & 2 are knockout. Quarterfinals are best of 3. Semifinals are best of 5. Finals are best of 7.
Winner of the NBA Championship gets the 3rd pick in the draft.
Here's how the NBA CHAMPIONSHIP TOURNAMENT would have looked this season:
|1||San Antonio (62-20)|
|8||Golden St (51-31)|
|2||Okla City (59-23)|
|3||LA Clippers (57-25)|
Here's how the RELEGATION TOURNAMENT would have looked this season:
Here's how the PROMOTION TOURNAMENT would have looked this season:
|11||LA Lakers (27-55)|
|1||Brooklyn (44-38)||7||New Orleans (34-48)|
|5||New York (37-45)|
This model keeps every teams fan base engaged longer, and in my opinion , just makes for a more interesting league in general. While the Mavericks would have narrowly avoided the Relegation tournament, can you imagine the excitement this format would've added to the regular season? Position in the table (the standings) would have been SO vital for older teams, like the Spurs and Nets.. And the fact that draft picks are decided by the playoffs as well would automatically take care of the "tanking" issue. The highest pick the winner of the draft lottery could hope for would be the #4 pick. Do I think this will happen? No. But it would DEFINITELY be far more interesting than the current NBA format.