Out of curiosity, is it possible at this time to have a completely flat world, with no terrain features what-so-ever, in order to test the limits of the custom building creator / our imagination?
Whether this would help the Devs at all, I’m not sure… but I know it would help me a lot 
that would be one heck of an idea. but for the time being you might just have to try to find a see that has the flattest possible area
Well, there’s Microworld… however, that’s mostly for modding, I would say.
You could always command your buildings to insta-build without materials if you want to try just building things.
Thanks, @Moai. Instant Build is just “IB” in the console, right? Will give that a go, should help speed up construction.