I don't know about anyone else, but I am a bug fan of Alice In Wonderland. I feel like an Alice In Wonderland themed world would be cool. I haven't really thought it out that much, which is why I should think before I post but I wanted to post this before I forgot! I am excited to hear your feedback and ideas. If anyone has played Alice The Madness Returns this is more what I am leaning towards, or the original book. Just typing up some ideas before they float out of my brain, I hope you like them.
Avalon takes inspiration from Alice in Wonderland. Remember that boss, the Jabberwock (like the Jabberwocky) and the Toadstool Village in the Wild? Those are just a few examples.