Yeah, good idea.
I think the latter is more likely. Out West, I think the alignments are obvious, but when it gets to the middle of the country things get a bit stickier.
I'd probably go with:
SEA-POR-SAC-GSW (Northwest)
LAL-LAC-LV-PHO (Southwest)
UTA-DEN-OKC-DAL (Mountain)
SAS-HOU-NOP-MEM (Gulf & River)
MIA-ORL-ATL-CHA (Southeast)
MIN-MIL-CHI-IND (West Lakes)
CLE-DET-TOR-WAS (East Lakes)
PHI-NYK-BRK-BOS (Megalopolis)
The trickiest bit here, I think, is to avoid the temptation to keep Texas and the Pelicans together. If you do that, either MIN or MEM gets really orphaned. Minnesota is probably a bad option to get sent to a Mountain conference, but you could swap DAL and MEM without too terribly much imposition on anybody but Memphis. WAS is the other team that seems to get a rough draw here. You could swap WAS and BOS so that Boston gets the rough draw but I don't really see a way out of that situation either.
You and I are really close with our alignments.
In the East, I think Washington fits better with Toronto, Cleveland, and Detroit from travel/distance perspective (it's shorter). And Boston fits better, clearly, with New York, Brooklyn, and Philly from a regional and rivalry perspective.
So I think you've got that one spot on.
The only difference I see is that I did group all three Texas teams with New Orleans. It just makes too much sense geographically and in terms of travel.
But I get your point re: Memphis. I can see valid arguments for Dallas and Memphis swapping places. There are pros and cons to both.
If the NBA went with a 6/5/5 division split, you could group OKC-MEM-DAL-SA-HOU-NO all together which would create a really tight super region.
Under the 6/5/5 format, you could have the following:
West:
OKC-MEM-DAL-SA-HOU-NO
LAC-LAL-PHX-LV-DEN
PORT-SEA-SAC-GSW-UTAH
East:
MIN-MIL-CHI-IND-DET-CLE
TOR-BOS-NY-BRK-PHI
WAS-CHA-ATL-ORL-MIA
The Wizards are really the only sore thumb fit in the East under this scenario, but they are the furthest South of the group of North West teams and even the most remote distance to them (Miami) is only a 2.5 hour flight.
I assume the NBA would prefer the 4x4 division format and alignment, but you never know. Again, there are pros and cons to both.