What do you want to see from Retro Studios?

[Soundwave]

I'd like to see them work on something mideval/mythical, but not Zelda.

Do something new, they've earned the right to try something on their own. Aonuma's team already has Zelda and Kamiya at Platinum Games is begging for Star Fox. There's no need to saddle Retro with another 20+ year old IP.