I am sure my idea has been mentioned in some form somewhere but:
Make it USA All-Stars vs International All-Stars, this would be huge for bragging rights. Just look at Lebron lining up other American All-Stars for the Olympics. I think the large majority of players would be into participating.
You could even take it a step further and extend All-Star weekend to a 3-4 day affair and make it:
Round 1: East USA All-Stars vs East International All-Stars and West USA All-Stars vs West International All-Stars.
Round 2: Winner of Game 1 vs winner of Game 2, that way you can still have east vs west for the finals which would determine home court for the finals of the playoffs.
I think this gives players more to play for during All-Star weekend. You could even have a cash bonus for both round 1 winners and the round 2 winner to further sweeten the deal. Bragging rights, cash and home court advantage. Plus you give a platform for even more players to showcase their talents during a huge event that millions tune into. Maybe it would feel a little watered down but being top 40-50 in the world is still a big deal.
Each player on the winning team gets 3-5 extra timeouts/coach's challenges that can be used at any time in the regular season or in the playoffs