I'm not against branching out into mythology and folklore from other parts of the world, but I think that European stories should definitely take the center stage. Grimms' fairy tales and the Arabian Nights are both large collections of stories, and there are still many that haven't been incorporated into a KQ game.
Speaking of which, Valiento, ATMachine and I recently discovered that several characters and elements from the original series (i.e., Genesta, Lolotte) actually originated from several obscure fairy tales that were all from a single collection of fairy tales compiled by Andrew Lang.
There are eleven other books by the same author. Some of the stories contained in them are very familiar (Rumpelstiltskin, The Three Little Pigs, etc.), while others are completely new to me. I'd be interested in seeing bits of these more obscure stories making an appearance. I'd also be interested to see some lesser-known mythical creatures from European folklore appear, and even something as small as a superstition about the supernatural could play a part in a puzzle (e.g., stepping into a fairy ring during a full moon, four-leaf clovers allow a person carrying it to see fairies and can also break enchantments). I'm sure the Rip Van Winkle story would also fit in fairly well.