Dot just seemed like an arrogant snob... ..."Oh look how cute I am! I'm the cutest one in the world!" Oh, and then later on she became an ANGRY arrogant snob.
I didnt like yakko much. Mostly because "yakko" had to "yak." I felt that all the good lines were given to him, rather than shared.
Wakko gets my vote because hes the cutest (forget dot) Maybe his accent helped. And like Felix the cat, he always had that bag of tricks.
Wakko also had his great moments. For example remember when they all met Pip? Yakko, yaked. Dot said "I'm going to hurt my brother badly." and Wakko in a calm cool voice said... ..."go away." I just loved that! That made the episode for me!