The ultimate issue with removing maps is that most players do not have the technical skill or patience to assemble a masterpiece of general use terrain. And then the ones that do, do not actually share their talents at all. Upon scanning through the server lists on the Blockland website, I see a lot of private servers with these really awesome terrains that I would absolutely love to implement, but can't get my hands on because they're locked behind a password. Then they literally vanish into the abyss, never to be seen or heard from again.
I wonder how many of these people are building their terrain and want to be left alone while they build.
I like to have my server open while i build so people can join and entertain themselves too.
But, I can see that it's easier for someone to get in the way while you're building with big terrain blocks.
That said, there may be plenty of users who do build complete terrains and then never release them or even host them to the public.