I'm going to go with the Bill Simmons question of "if aliens landed and we had a single game for the fate of the world, who are my first 5 picks to be on the team?".
KD
Kawhi
LeBron
Steph
Jokic
It is hard to leave Giannis off since he can get a team to 50 wins almost by himself, but in a single game I'm going to go with the guys above.
As a thought exercise, with some of the players behind these guys, you can ask... "if I swapped X player with one of these guys, how would the team results change". For example, if you swap Steph and Luka, which team does better this year? I think Dallas improves with Steph and GS gets worse. Barely.
Swap Giannis and Jokic, which team gets better? (Yes I realize they play different positions). Close one here. I think the role players in Milwaukee get marginally better and the team wins a few more games. For me, it is very close between Giannis, Jokic and Embiid. Swap Jokic and Embiid and both teams might actually get better.
Jimmy Butler isn't getting any mention. This year he was #5 in PER, #5 in WS, #3 in WS/48, #6 in VORP
Zion is #4 in PER, #11 in WS, #13 in WS/48, #10 in VORP
Gobert is #2 in WS, #4 in WS/48, #14 in VORP, #15 in PER