Adding random Pokemon is pointless since people could easily raise the argument "Why didn't you add [insert one of the other 710+ Pokemon not in the game]" (I took out Jigglies, Pika, Lucario, (3) Pokemon trainer, Pichu, and Mewtwo).
Ridley just has porportion issues that his design would be very messed up trying to get right. Not just in regular stance, but picture how they would have to contort his body whenever he attacks and uses his smashes and stuff. And where the hell did this "Bowser is scaled down" stuff come from? He's had many appearances like in the Mario spin-offs where he is not even that much bigger than Mario! Mario Kart, Mario Golf, Mario Baseball, Mario Tennis, Mario & Luigi series, Paper Mario, etc. Plus, Ridley just doesn't look like he could pull of the character vibe the others have. I mean, he looks like some sort of realistic-esque dragon. I feel like his design just doesn't really have a...personality to it. I don't know how to explain it, but all the character have it where their look and their characters all have that...humanoid or anamorphic feel to it (I'm not sure if that is the best terminology, so forgive me if I am not making my case clear enough). I just feel that adding Ridley's character wouldn't match the style and feel as the rest of the cast.
King K. Rool's issue I think is the fact that he hasn't been relevant in a long time. He hasn't really done much in the last decade, and adding him over Dixie Kong or even Cranky Kong seems incorrect. If another DK rep is to be added, I belive it'll be another Kong. I know that "there needs to be more villains" and such, but we shall see if Nintendo agrees with that statement.
