I absolutely love and adore the concept of imagination-based body form in combat, but imo Oda executed that fresh concept so badly.
My headcanon on how to fix this:
- Instead of getting Nika fruit for granted since the beginning, Luffy shouldve not only unlock the full potential of Gomu2, but even nurture the fruit to grow by himself to become an entirely new fruit, basically creating a new devil fruit and form himself
- No "Luffy Toons" at the beginning. Instead just draw regular white-haired Luffy attacking in regular Oda-style manga art, but he's now able to freely change in muscle mass. This will be added by people including Luffy himself, Kaidou and others revealing what Luffy is doing in combat ("His punch becomes unbelievably strong! He can freely increase his own muscle mass?!") ("He just slowly tapped Kaidou's seastone club...and it breaks?! Did he just amplify his own kinetic energy as he please !?")
- If Oda wanna make Luffy into Joy Boy, then the name Joy Boy should not be a character living in the past, but a hopeful dream (not a prophecy) from people of the past...about a character in the future (which Luffy fulfill by becoming).
- Luffy should be laughing not in gags but in insanity, as in he starts to be addicted in becoming mad powerful and really like it when he's having no consequences from his actions.
- At the next level of mastery, then Oda can start drawing Luffy's body as Toon.
But it should be eerie, not cute. And the art / animation should be actually connected to his performance in combat. As he activates Toon Mode and becomes cartoon, his body and existence start to be unaffected by law of physics, ignoring attacks from his enemies like a cartoon would.
And certainly his enemies and other characters should never be shared this characteristics. No cartoon version of enemies. Rather, the effect of Luffy's attack on his enemies should be even more real and raw than before, just like pre-TS WB getting his head blown off by Akainu.
Luffy can suddenly make his own head much bigger cartoonishly like a balloon, but then eat Kaidou's head clean off with gruesome art without the reader even anticipating about it. Creating a contrast between Luffy's silly body and the enemies' mangled body, just like Madoka Magica's monsters killing real people with contrasting animations. So Luffy is laughing at his enemies, not laughing together with them.
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Sorry, not meaning to derail your thread...just imagining this scenario tho.