You’ve seen the creativity from all the people who played Minecraft and now you see people building awesome stuff in Landmark. Everyone who got creative that way and just know how to build that way could be designing on Unreal Engine.
Imagine all that attention brought on Unreal Engine if it allowed for in game level building like in those games mentioned. Sure Unreal Engine editor is much better and faster tool obviously but having the option of being in your gameworld walking around and building with simple tools, you could build a simple house that you could then edit further in the editor. To take it further to the Minecraft like editing you could have a server with a design team building stuff together.
Would that kind of building ever be possible in Unreal Engine?