He was a bad face character.. However, that doesn't mean that it couldn't be fixed. Just make him a mask character. It worked well for Inside Out, and they never use an actual face for other regular human characters for normal meet and greets such as Captain Hook, Lilo, Woody, Jessie.... so I think it would work fine for Hiro.
Plus the main problem with Hiro's face character, in my opinion, was that the cast members portraying him were way too tan, and their eyes are too small. Otherwise, it would work great. They just did an awful job in type casting.
He may supposed to be asian, but honestly, he just looks like a normal American to me.