Welp, here's my two cents on terrain and such:
I used custom maps a lot, usually when I wanted to invoke a sense of scale and exploration. Have you ever tried to assemble a detailed city map that spans further than the average player's render distance or a massive sloped arena for long range dogfighting or vehicular combat using modter or the like? Its one helluva task, even more so if you want it to look good or naturalish.
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.
Feel like the next task would be to make build sharing more important. Then provide some half decent terrain generation code that isn't super spam junction and can make some interesting shapes; or something to just make building large builds easier than one brick at a time.
Or something idk.