I don't think that Sakurai actively hates K. Rool, it's just that circumstances were always against the King. 64 was the first game, with an uncertain future, they could only afford doing protagonists. Melee had rushed development, so the team could afford doing only a few actual newcomers(not clones). They understandably gave priority to other more requested characters such as Bowser, Mewtwo(both considered for 64), Peach and Zelda. Iirc also was in the middle of the Rare buyout bull****. In Brawl, once again, another character got in the way of the King, this time Diddy Kong; understandably, the sidekick got priority over the villain. In smash 4, Sakurai probably felt like the King's popularity faded out because it hasn't appeared in ages and that's probably why he excluded him. Luckily, we have this ballot to ultimately prove that our King is the perfect choice. Excluding him now would be like excluding Bowser after the Smash 2 poll.