We don't often report on leaked and unconfirmed content, but when we do, we have good reason. It appears that Genshin Impact may update older character models in the future, to hopefully bring designs in line with the sleek new Nod-Krai characters.
We all know some of the earlier designs in-game are less polished than most later characters. Comparing Genshin Impact's Diluc with Alhaitham or Neuvillette, for example, shows that the former has rather buggy eyes.
Allegedly, characters including Genshin Impact's Albedo, Ayaka, Arataki Itto, and even the Traveler may get some design tweaks. There's no information as to what this may entail, but hopefully, Itto will get the muscles he deserves as the one and Oni. Leakers, including Hoshino and Uteyvat, comment on this and suggest it's happening in the 6.x patches. Again, this is currently just a leak, so take it with a pinch of salt.
When you see newer characters like the aforementioned Alhaitham or Genshin Impact's Ororon with their slim but really quite muscled arms, or Genshin Impact's Wriothesley's larger frame, it's clear to see that models have changed over the years, and just makes Itto's noodle arms that much more noticeable.
There's no reason why these updates can't happen. While not exactly the same, Zenless Zone Zero gave debut character Ellen a refresh with new moves within a year of its release, and Honkai Star Rail recently updated kits of Blade, Silver Wolf, Kafka, and Jingliu. Hoyoverse isn't scared of fixing up older content, so why not make Albedo and Ayaka's hairstyles a little more interesting?
We'll have to wait and see what happens in the next Genshin Impact updates, and keep an eye on the Genshin Impact banners to see if we can pull for the newly refreshed characters.