because it *****?
No, but its because it provides alot for the way TL was designed. He's meant to have an amazing on-stage presence at the cost of a bad recovery. His current UP-B allows him to score kills way earlier than younglink ever could've dreamed. Not to mention that it combos with EVERY SINGLE ONE of his projectiles, bair, usmash, utilt, dthrow etc etc so it's really amazing as a combo finisher. It also makes so anyone facing TL is threatened to not to be above him, or they will eat UP-B. Overall, it just synergizes really well with his character design.
Yeah. The deku leaf from WW is much more canon than a midair spin attack, but i would imagine it would give TL unnecessarily amazing recovery distance on top of his already amazing onstage game. On top of that, he'd lack a reliable kill move that follows his projectiles. It just doesn't fit how he's designed. He would also be really vulnerable in the air during recovery (similar to snake) so he would retain much more of the original flaws that young link had in melee. Lack of reliable kill moves to follow from projectiles, a very predictable recovery though good distance wise, would render him vulnerable and you wouldn't be able to **** as hard :D
yeah, leaf would be cool, but nah lol