>mythical pokemon
>has unique ability to learn every move
>makes it genuinely feel special without just relying on its title as "mythical"

Why don't they do this any more? In red and blue, Mew was super rare and could learn every move and Mewtwo was the last pokemon you caught and was the most powerful pokemon. They weren't special just because the game said "oooh they are legendary!" They were special because they were legitimately good.

This point is also true with the bird trio too, to a lesser extent.