I'm just saying that older niche characters typically only appeal to hardcore Smash fans. Newer characters have the advantage of being recognized by both hardcores and casuals.
I'm trying to look at this from the perspective of a person who has never played Smash before. To an extent, I do believe Sakurai should take into consideration relevancy when he's adding newcomers, and the ballot doesn't do the best job at that. Even though characters like Issac and Geno would be insane for us, not many people are going to know who they are, and that probably wouldn't interest them. However, they might recognize the weird squid people from that new game where you shoot ink at each other, or the funny man with the long springy arms. Even if characters like these aren't crazy popular in the Smash community like K. Rool or Ridley, their relevance makes them more likely to be recognized. That's what I believe Sakurai's goal should be; to pick out the characters that would appeal to the most people.
Now I'm not saying that older popular characters can't be in the game, but I definitely think popularity by itself shouldn't be the focus for newcomers. The ballot only focuses on popularity, and I stand by my claim that a roster composed of only those characters would be pretty underwhelming.