It's worth noting in hindsight that Sakurai did this for you guys. For the hardcore Smash players and DK fans who had built this shrine for Rool. I'm not really one of these people because I like Rool and was definitely happy to see him in, but wasn't ultimately passionate about him either way. But ultimately he's in because of the explosive following you all created. And I say this because the point of contention about his relevancy and the scale of how iconic he is is a very valid point.
To put it into perspective, I've heard followers laughing off arguments about how modern kids don't know who K Rool is, hurting his chances. Well I just got done chatting with a couple coworkers, both of whom are my age, about the Smash reveal. Both of them are big-time gamers, especially one of them who is a Castlevania die-hard and plans on buying Ultimate to play Richter. They're both 27. Yet when I mentioned the highly desired King K Rool...
They had literally no idea who he was. They knew of Donkey Kong. They knew of Smash and have played in the past, but have been off the scene for quite some time. They were old enough to see DKC 1 launch and actually play it. Yet they had never even heard of DK's Bowser.
This demonstrates both how poorly he's been represented in his series and to gaming at large, as well as how powerful his fan support truly was to have still earned him a spot.
He's here, and it really boiled down to you guys, just like the Ridley supporters. You should feel proud.