MK, Peach, Falco, Wario, and Olimar. ESPECIALLY Olimar. I hate him.
DK isn't overrated. In fact Diddy used to be VERY underrated along with him. But ever since Diddy Kong went higher in tier lists he got more popular. DK didn't get much more attention, despite being pretty awesome.
Oh and speaking of Diddy receiving more attention (though well deserved), ever since Wario was declared 3rd highest in tier lists, he was suddenly more popular. Definite proof that people get influenced way too easily by tier lists. Before that nobody cared about him, now everybody's all over Wario like he's the second coming of Meta Jesus. He's not even that good. Sure he's good, but D3 is still better by a mile. Wario has these weird moves and specials that don't seem to help at all. He's only got the advantage of being both quite heavy and fast at the same time.