You know what occurred to me?
The Commons should be Legendary.
Here me out.
They are our first "babies" in the game...
but quickly become forgotten because they simply can not compete with the newer and faster monsters that are always coming out.

That seems a little sad to me.

I know they can be ranked up...
But, they just can't keep up.

Know what would be awesome?

They could "evolve" into Legendary monsters!!

So... Firesaur could become "Legendary Firesaur"!!

Maybe they could earn "status points" when you use them in battles that they survive that could be accumulated until they've earned "enough" to evolve

Or maybe... There would be special dungeons or adventure map battles they'd need to complete.

But... I think it would be awesome to find a way to make our earliest babies an active and powerful part of the game throughout our gameplay experience.