It's not that the roster is small. It's just that Agitha's not that interesting as a character. Her appearance here is just so random. I know Agitha's a popular character in Japan, but we're talking about a country that adores weird or hated characters like Tingle & Slippy Toad. I see her just like those characters & it gives me a good reason to hate her (along with her being an unmemorable character).
OUCH! Doesn't that seem a bit harsh and ethnocentric? I mean, it kind of IS their game, and they're allowed to appeal to their Japan fanbase, too. We aren't the only country on Earth. Heck, I could go so far as to say we're lucky to even see this game come stateside. While it's becoming increasingly popular, there used to be a time when games like this would never leave Japan, leaving U.S. fans screaming "Unfair! Japan gets all the cool stuff!" Hating little ol' Agitha for such an ethnocentric reason is kind of extreme, don't you think?