I like Kozaki's style, but i prefer variation, if Hidari comes back that would be great, his designs are some of my favorites in the franchise (Alm).
If they get someone else i would love to see Akihiro Yamada; or Akihiko Yoshida, i'm in love with his art, from characters to background, though i don't know if he works outside of Square Enix. Kimiko Fujisaka is great too, and if they want something crazy then Tomomi Sasaki.
Dream scenario would be Kentaro Miura.