This reminds me of the mystery box joke from Family Guy.
I mean Kawhi Leonard's Kawhi Leonard. But Jaylen Brown could be anything... He could even be Kawhi Leonard.
If you do the trade its because our time to compete for a title is now. Kyrie, Hayward, Leonard, Tatum, Horford is a championship core on par with GS. That can be viewed as more valuable than Jaylen's sky high potential.
If Tatum continues to develop you'll have to make some hard choices in 3 years but by then who know's what the NBA will look like? Brown for Leonard is bird in the hand.