A farm map for murder. You could have a huge fenced in area filled with a few barns, cattle ranches, wheat fields, windmills, chicken coops, and even a farmhouse! On the outside of the fence, you could put an enormous forest. This is a map you could build in a seed randomly generated by MC. Instead of having to build it in the void. 
A few pics I found online




Just an idea, not surprised if this does not happen though... oh well

A few pics I found online




Just an idea, not surprised if this does not happen though... oh well



If you can support them with thoughts on what makes the map unique gameplay wise, or how the layout should be, or just 1 particular detail you'd really like to see in any map (like a mechanic such as slimeblocks).