Making Elite Marks Look More Unique?

[zeth07]

Well, according to Lore:
"Only when a creature grows more cunning, more aggressive, more deadly than its brethren is it worthy of a name.
Though these creatures can appear hauntingly similar to existing monsters, their ferocious nature sets them apart from their weaker cousins."

That's understandable, but part of what I'm getting at is why do some monsters in fact look unique (like Maahes) and the others don't? Why doesn't Maahes just look like any other Coeurl in this case if that's what is acceptable?

This is coming from a game design/decision making point of view and not lore-wise. Lore-wise they could've just made Maahes like the others but they didn't. So why did they not do that for others is what I'm asking about as well.