I brought up the idea for having additonal cool+ /j mountain /j dessert /j plain and /j ocean maps a while back. All I got out of it was people feel that the current maps are absolutly perfect and there is no point in making new maps with specific building in mind.
I think if we added a map specifically for people who love building the large buildings that they build in cool where they have to clear an absolutly massive ammount of space for the base to be flat, or where they want to build ships more massive than anything possable in the cool oceans, they should be able to have a world set catering to that. (although plains does not mean it has to be an absolutly flat map, could have some higher spots and lower spots to make it interesting, but overall relativly flat, not too deep and a very high build ceiling to better facilitate tall and wide towers and other builds that require large ammounts of flat land. The argument is that only flat levels are boreing, but they're not the only levels and they're ones people would specifically have to choose from out of the list of many worlds)
Then, a mountains level where you could build massive tunnel complexes, massive bridges over large spans, and really anything that would take well to having very large mountains which extend to the build ceiling, and have about 4-5 blocks all around below them to tunnel between mountains. (Plus have some mountain streams through them)
Dessert could range from another flat-ish map to a partially flat map on a slope with some dessert mountains or dunes around it. I don't know exactly what you could build there, but it would be a very cool thing to see what people would build there.
And, of course, an ocean map, would be used for large ships, naval battles, underwater builds and who knows what else that would require a larger ocean than the cool ocean. It would be like having the cool ocean all the way around the map and beaches surrounding it, with some islands in the middle of the ocean. Not a totally flat ocean with absolutly no obstructions, but rather one where anything ocean or island could be built.
I think if we did something like that, we would save on room in cool worlds for general builds, and the people who build specific build types like ships, tunnels, towers and buildings that take up a lot of land, (maybe cities) or really any other build requiring large ammounts of flat land, would all be very pleased, and the jack-of-all-trades cool map would be good for everybody that wants to build general buildings in an eclectic setting with whatever else there too.
Now if only somebody could get tnt to work... that would be soooo handy in sooo many applications...