Now that I could see a European Division of 6 teams and 5 other divisions of 6 teams.
Europe - London, Paris, Berlin, Barcelona, Rome, Athens
NE - Boston, Brooklyn, New York, Philadelphia, Toronto, Cleveland
SE - Miami, Orlando, Atlanta, Charlotte, Washington, New Orleans
MW - Detroit, Milwaukee, Indiana, Chicago, Minnesota, Memphis
Central - Oklahoma City, Dallas, Houston, San Antonio, Denver, Utah
West - Phoenix, LA Clippers, LA Lakers, Sacramento, Portland, Golden State
I like that. Memphis and New Orleans (to a lesser degree) are slightly out of place geographically, but otherwise I think that works out pretty well.
To work out the schedule you play 80 games, 4 games against your other 5 divisional opponents (20 games) and then just play a home and away with every other team 2 games * 30 opponents for 60 games. I think eliminating the 2 games would help a bit with the travel constraints and would imagine the North American teams would just do a 6 game road trip in Europe every season. You eliminate conferences doing this and just guarantee that every division winner makes the playoffs, but seeding everyone 1 to 16. Since you would have an even schedule (outside of division) I think that makes the most sense. The only tricky part would be the playoff schedule with the European teams. I mean imagine if Athens is playing Portland. That would be a crazy travel schedule for a playoff series.