He has great ninjutsu but lacks in taijutsu if he got Lee's speed and CQC abilities he'd be so OP.
more durability, more speed, more strength, better technique, he'd be helpful against someone who ninjutsu doesn't work on. it's called being verastile.Because of a thing called balance? Dunno.
Why would he focus on something he's mediocre at instead of improving his (already) awesome ninjutsu?![]()