Quote Originally Posted by noob View Post
It is because fundamentally monsters are just adventurers but with some odd traits.
it is the same link as the link between adventurer hd, adventurer skill points and adventurer bab.
Exactly. The problem is that those things are determined by type, not the monster's niche, which can vary from monster to monster regardless of what monster type they generally are. Hence why monster HD needs to be separated from Type.