Trae limits his team in the playoffs since he is not a two way player. Trae is steph curry light. He is shorter,, not quite as elite of a shooter, doesn't move off the ball as well, more attitude, etc. Steph could hide behind Klay, Green, Kevon, Wiggins, and others who were all above average or elite defenders. It could be argued that Trae could do the same but I wouldn't see the Warriors being a dynasty with Trae instead of Steph.
Trae would require elite defense around him.
I prefer the fit of Luka and Lauri. It just sounds good too. Lauri is the perfect pairing with an alpha like Luka. Kessler, Hendricks, and Lauri are pretty darn good defenders to put around an elite scoring threat, but Luka plays with more gravity and he is a better passer than Trae. Lauri and Luka gets you top 3 in the west for years to come.