I love Super Mario RPG and I like the characters of Mallow and Geno, but they were supporting characters in one game released like 17 years ago. I know about Geno and that poll years ago. I just feel that there are far more important and iconic characters to include, even in the Mario series. Paper Mario is an extension of Mario, but I think he makes more sense. He's different enough from regular Mario to deserve consideration. I realize Geno and Mallow are also different, but Paper Mario has starred in four games, the most recent having been released last year. Even if they would be considered as obscure characters like Mr. Game and Watch and R.O.B., there are better choices, like Sheriff or Mike Jones (as previously mentioned in this thread), both of whom would represent new series to Smash Bros.
I haven't played Dillon's Rolling Western or Sakurai Samurai, but considering they're newer, I wouldn't mind seeing representation from those games. I'm mainly hoping for more variety in IP selection. If a character is from a series never seen before in Smash Bros., I usually favor that character over others. If a character is from a series already represented in Smash Bros., I think that character should be a really important one from that series. For example, I personally like Prince Peasley and Fawful from Mario and Luigi, but like Mallow and Geno, I feel other characters from Mario (and in general) deserve a spot more. So, if another Mario character were to be chosen, Paper Mario, for example, would trump Prince Peasley or Geno.