While I agree, something that should be noted is that the majority of ballot-backed characters are from the base game. Banjo and Kazooie are the only DLC fighters who are primarily chosen from the ballot; Erdrick and Steve likely did well on the ballot, but they were probably added by virtue of Dragon Quest being massive in Japan and Minecraft being massive everywhere.The more I think about it, the more certain I am that the Smash Ballot is probably still being used to determine which characters are popular among fans. Just looking at the newcomers and dlc characters in Ultimate shows that the Ballot is probably fairly influential (K. Rool, Ridley, Chrom, Simon, Inkling, Erdrick, Banjo and Kazooie). That being said, I think that means characters popular with Smash fans during Smash4 and 2015 have a much better chance of getting in than characters who gained more support recently.
In other words, the DLC still uses the ballot, but not extensively. Based on FP1, I'm expecting only one or two characters who did super well on the ballot.