LOL, Misty's not important? Really?
How is Misty more important than any other character? She's a short-lived character that had one of the smaller roles for a female protagonist (only above Iris so far), and when AG was airing everyone agreed May had a far bigger role and was more important than her. Then Dawn had an even bigger role than that.
How is Misty more important than any of the girls who came after her? I can't think of a single thing. She's a short-lived minor character that was replaced by the far more important May in AG, and then they went onward to Dawn, etc. from there.
Misty's actually retroactively become one of the least important characters in the entire anime. You don't even have to know who Misty is to watch Pokemon, as you can now watch almost 450 episodes of Pokemon and not see Misty in a single episode.