I think what people are missing about "Medical ninjutsu" and "CES" is the "delicate Chakra control" description.
Naruto eventually mastered chakra control, but nowhere has it ever been stated he can control chakra DELICATELY.
Same with Sasuke.
There is nothing delicate about Rasengan or Chidori, they are explosive and sharp respectively.
If ninja like kakashi or Sasuke were as "delicately refined" as say, Kabuto, they would use Chakra scalpel instead, not the very wasteful Chidori that sapped Sasukes strength after 2 uses, and kakashis after 4.
Chidori was incredibly inefficient until Sasuke proved it could be modified into other actually useful jutsu like senbon and spear, and even blade.
I am not saying current sasuke/Naruto could NOT master it, i am saying that the TYPE of chakra control is against their very natures (Sasuke is Precise like sakura, but not delicate, Naruto has mastered containing his chakra while manipulating shape, but never complex forms other than arms, and NEVER delicately).
They would have to practice A LOT to master a different type of chakra control.
Naruto eventually mastered chakra control, but nowhere has it ever been stated he can control chakra DELICATELY.
Same with Sasuke.
There is nothing delicate about Rasengan or Chidori, they are explosive and sharp respectively.
If ninja like kakashi or Sasuke were as "delicately refined" as say, Kabuto, they would use Chakra scalpel instead, not the very wasteful Chidori that sapped Sasukes strength after 2 uses, and kakashis after 4.
Chidori was incredibly inefficient until Sasuke proved it could be modified into other actually useful jutsu like senbon and spear, and even blade.
I am not saying current sasuke/Naruto could NOT master it, i am saying that the TYPE of chakra control is against their very natures (Sasuke is Precise like sakura, but not delicate, Naruto has mastered containing his chakra while manipulating shape, but never complex forms other than arms, and NEVER delicately).
They would have to practice A LOT to master a different type of chakra control.