I already got most of the characters I would have asked for in the game already (prior to Smash Ultimate), Isaac is kind of the last 1st Party character I really want in the game (who still has a shot); with the exception of Tails, Agumon, Vaati*, Lyn and Nightmare, everyone else on my request list in my Signature are pretty much all characters who my active support for came after joined these forums.
*I don't consider Vaati to really have a shot at playability mostly because he's competing with a lot of Zelda characters, and may or may not have rights issues with Capcom. That aside he's still lower on my wanted list than Isaac anyway.
This is a good discussion topic - who do you support from before, and who have you gotten to know because of the forums?
For me: I never really did the speculation thing for Brawl. After release, I woud fantasize about Midna or Ivy (Soul Calibur) in the game, but nothing more than that.
Sm4sh speculation was mostly revolving around returning vets for me. The big ones I wanted to see return were the Pokémon Trainer as a team (I thought the idea was genius and they were all really fun to play), Mewtwo (the most painful cut since I love Gen 1, and he's so cool), and Wolf (for my cousin, since he always played Wolf). Also Ganondorf, but he ended up in (albeit with a severe derplord makeover). But that was also when I joined the boards, so I got swept up in speculation, particularly for Rildey and K.Rool, despite never having played a Metriod or DKC game. I still supported Midna for myself as well. I will admit that this led to my disillusion with Sm4sh, since I had so many characters I liked and none of them made it in at all.
Now, I still was on the K.Rool and Ridley trains (I finally did play DK64) because I'd gotten swept up from those threads a few years ago. But seeing all of my vets return was truly the best part, and I'll admit that Squirtle actually hyped me a bit more than Ridley. My current wanted list now is mostly my own now that various third-party doors have been blown open - Dovahkiin since I love the Elder Scrolls series and the game was beautiful, despite the game being Western and only having a 6-years-later port as its connection to Nintendo; and Tails since he was my first ever video game character back with Sonic 2 (even though I really don't know what happened in the Sonic series after that, I just know that Tails is Sonic's BFF), despite Sonic already having a rep. I still drag Midna along even though she's disconfirmed - I'm of the opinion that DLC can promote a character easily, it just hasn't happened yet - or comes in her Twili form as a Zelda echo. Ivy is still there, but I'm not going to go out of my way for her. But Urbosa did also steal the spotlight in BotW for me so I'm for her as well. Skull Kid I'll admit is a bit bandwagony. I loved Majora's Mask, but I'd take Midna or Urbosa over him. Still, he's leagues above any other potential newcomer for me.