Oh, no, Kirby definitely deserves to be on here. Hell, a lot of Nintendo characters deserve to be on here. With their designs, you know who they are. If someone sees Mario, even if they've never consumed a piece of media for that character, they know it's Mario from the design alone.
There's a fine line between recognition through popularity and design. But with characters like Superman or Batman, everyone knows who they are even if they haven't seen them in a piece of media, because of their design and some word of mouth.