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.
No need Euro vs USA players. Just make 4 all star teams and do it as tournament. With that way we wouldn't speak the names who deserved ASG but their spot is way too filled by big fishes. And teams would gonna in balance. By International vs USA; International team would have some mediocre players too such as Olynyk or Valanciunas etc.