How amazing would it have been if there was a map creator, this game almost seems meant for it.

It would be nice, but that's how it is.
You could try and see if the map-maker is still there. I don't know if ACE Team intentionally disabled it or not.

There's always Rock of Ages 2.

Making maps would be extremely difficult unless we would have made custom chunks that could be stiched together for the purpose of custom maps. I agree a map editor would have been awesome though...

yes making the user maps look fluid would be difficult, but the main structure of the game is blocks I would say make the style of the user maps kind of like a schematic I mean you have a premise already in place for such a thing with da vinci in your game you could make the user maps look like old brown paper schematics with da vinci style scribbles as the back drop and just using cubes to create the maps kind of give it a cell shaded pen and ink scribbled look.