Ridley and K. Rool, easy. I am of the opinion that Ridley is, in fact, too big for Smash, but the former two I take way more issue with personally. Captain Toad just isn't cut out for a fighting role in my opinion, and to see him get in over pretty much any other Mario character would make me at least a little miffed, and Waluigi needs to **** off and die like the overexposed, unfunny meme he is.
Would you rather Mario's default costume replaced with 7 GRAND DAD and all his alt costumes removed, or remove all of Shulk's costumes except for Shirtless "im really feeling it xD" Shulk? Basically, pick your poison between two run-into-the-ground memes.