ExploderWizard
Hero
So, why not have a single stat block and you can slap on whatever humanoid description you feel like? Or, better yet, a collection of stat blocks ranging in power level and tactics, that you can slap on whatever description you like?
Why does every creature need a new stat block when there is no particular mechanical difference?
Exactly. Why do we need 5 or 6 completely different stat blocks for goblins when one will do then just add abilities based on role. This would allow for more race/ ability combos without reprinting statblocks for the monster.
The defining difference is that the method you describe is simply cloning a set of combat statistics with new skin. It also points out that ecology and culture are meaningless. There are major differences in an air elemental and a hippogriff beyond combat statistics. If not then it is a bland flavorless world indeed.