To be honest, the only thing I'd want to see in a modernised Klonoa is bigger and more beautiful backdrops, I can picture bloom effects being used a lot, making things look more shiny, and I guess "Magical".
I would also love to see harder levels, like in the vein of the bonus time attack levels in the games.
Otherwise, I think the games are perfect, beautiful, artistic masterpieces! If it ain't broke, don't fix it!
EDIT: Tell a lie! I would love to see multiple windbullet spirits that have different abilities.
Like you'd have the default wind bullet, then you'd have one with longer range, but slower, and maybe one that can bounce off things, among other things, and you can switch between them all!