I'm bad at fashion (In general, not just games -_-), so I haven't really dived into better looks for him, but I hadn't ever really given him any story, either.
I think he's just ended up being a Link-esque, quiet (but not silent) ever-smiling himbo type capital-H Hero. Loves to eat, loves to think, loves his friends and the star, and it's that smile - indiscernable, somewhere between empty-headed and total, unshakeable confidence, that both haunts and fascinates all who meet him.
A bit generic, perhaps - a bit of the embodiment of the "But what if you can't handle it?!" "Then I'll handle it" WoL meme. Everyone else can be cocky, or smart, or indignant, or wrathful, but the endless, burning determination of the mortal spirit against impossible odds? The tiny, shining mote in the overbearing darkness? A charred, bleeding, broken husk, still standing, throwing you a thumbs up and just the barest hint of that little smile?
That's my guy.
(Shadowbringer/Endwalker MSQ spoilers below.)
EDIT: He got the himbo shards from Azem - the pretty, the strong, the helpful. Ardbert got the rebellious do-what-it-takes bits. I like to think that Azem, to my WoL, is a lot like a completely powered up in-form Goku to regular-times sweet boy Goku - faster, stronger, smarter, but all still around and supported by the Biggest Heart. Not quite so sure my WoL's as much a ditz as regular Goku, but that's only b/c he keeps his mouth shut most of the time.