Name of Feature: The Dalek Invasion of The Universe.

Description: Daleks spawn way too often, for being as powerful as they are. They spawn randomly with no regard to reason or timeline. Their spawn rate cripples the existence of other mobs from vanilla minecraft and mods. If you go to the end, the endermen are a rare sight. Rather it's just become another Skaro. Daleks should spawn from specific randomly generated structures such as invasion ships, or time corridors. They would spawn daleks of a specific set. (Paradigm daleks would spawn just with paradigm daleks and time war daleks, renegade type daleks spawn with only renegade type daleks, imperial with imperial and so on). Dalek invasions cannot spawn on skaro. Gallifrey can only have time war dalek invasions. 

Lore/Brief Background: Throughout the show, Dalek design has evolved constantly. Only once or twice have the old designs been seen alongside more current designs. Furthermore daleks in game have overrun the end, and they do not drop end materials, making them way more rare, and making end farms impossible. Daleks also make starting a new game very difficult. Rather than being able to take on the daleks on your terms, like you can with all other mobs.

How does this affect gameplay: Quite simply, the game becomes easier and more balanced, as well as canon friendly. Daleks do not need to make the game so difficult that other OP mods are required, and keepInventory is not optional. The End is useless now, because of the daleks. This change would fix that.

Any Other Information: By no means am I suggesting Daleks be nerfed. A dalek by itself should be a deadly menace that can kill you with ease. But they should not be around every street corner all the time, they should not make finding other normal mobs so difficult and they shouldn't hurt the normal gameplay experience. 

I like this idea.