The biggest problem with the time dilation theory is the existence of Mother Carmel.
https://onepiece.fandom.com/wiki/Carmel
Mother Carmel lived on Elbaph for most of her life. And in that time, she seemed to age like any normal human would. Not slower. Not faster. Just seemingly the normal amount. She lived 50 years on Elbaph, and she noticeably aged by around 50 years, as far as we can tell.
The same goes for Scopper. He's around 70 years old. And he looks like a 70 year old in this world. He's not noticeably older or younger than he should be.
So, if there is some sort of time dilation happening, it's not happening in the areas that most Giants live in. Maybe there could be some sort of time dilation in the Heaven/Astral Layer? But, the top of Yggdrasil doesn't really look unusual. The top of the World Tree just looks like a regular (if giant) tree. So, if the time dilation is happening up there, it's not affecting the tree, as far as we can tell.
Personally, I think the time dilation theory is a non-starter. But, who knows? I guess Oda could retcon it in, if he really wanted to. I just don't see any proof for it, myself. It's a fun idea to justify a training arc, but I just don't think Oda is planning on going that way with it.
https://onepiece.fandom.com/wiki/Carmel
Mother Carmel lived on Elbaph for most of her life. And in that time, she seemed to age like any normal human would. Not slower. Not faster. Just seemingly the normal amount. She lived 50 years on Elbaph, and she noticeably aged by around 50 years, as far as we can tell.
The same goes for Scopper. He's around 70 years old. And he looks like a 70 year old in this world. He's not noticeably older or younger than he should be.
So, if there is some sort of time dilation happening, it's not happening in the areas that most Giants live in. Maybe there could be some sort of time dilation in the Heaven/Astral Layer? But, the top of Yggdrasil doesn't really look unusual. The top of the World Tree just looks like a regular (if giant) tree. So, if the time dilation is happening up there, it's not affecting the tree, as far as we can tell.
Personally, I think the time dilation theory is a non-starter. But, who knows? I guess Oda could retcon it in, if he really wanted to. I just don't see any proof for it, myself. It's a fun idea to justify a training arc, but I just don't think Oda is planning on going that way with it.