Minecraft's developers have explained why the Ender Dragon is bound to its own realm underground and not allowed to roam the overworld.
For a game about building and creation, Minecraft sure has a lot of ways to absolutely ruin all of your creations, and the progress you made towards accruing the materials for said creations. The developers at Mojang seem to understand that, with the CCO of Mojang Jens Bergensten admitting that they probably would not add the Creeper to the game today, despite being the series de-facto mascot, since the ability to destroy builds would undoubtedly be controversial if implemented 14 years later.
