Kirby: He can't talk. Because of that, the writers seems to not focus on him until a monster comes, goes berserk, and gets defeated by Kirby. In my opinion, Tiff and Tuff only exists because of Kirby inabilty of speech, and the writers focused more on them. Kirby not talking also just made feel to not have any actual personality.
Dedede: His whole existence is just a parody of his game self. He had a very nice character development through out the games. From being a King who stole Dreamland's food to a King who protects Dreamland, is a nice guy who is also one of Kirby's closest friends. The anime, has the most annoying voice plus a accent makes me want to rip my ears out. He isn't even Dedede that anyone would think of. He isn't at all kind, and if he was the next episode has him being a jerk again. Escargoon is just Dedede's good side that they never use. Dedede never has any kind of character development and he's not at all funny, just annoying and hatable.