Mine are:

More open areas that aren't enclosed in mountains. (EVERY LOCATION is encircled by some sort of mountain or a cliff)

Large open areas. (Think the Lower and Middle La Noscea size without the corridor feel)

Loot Tokens for Raids.

Moar S ranks. (Malboro that uses Stun + Bad Breath plz)

Weather specific mobs

Have like 50 other but I'm interested in others.