Well first I doubt many people were requesting Terry Bogard because most people believed that was never going to happen at all.
Also for the characters that I want I try to limit third party because there's so many legal negotiations that goes behind just obtaining the rights and it's entirely possible that those characters might not cross the developers mind; there's so many uncertainties that I rather not have investment in any particular third party getting in despite how much I would love to see them. So much as I want a characters like Dante I'm not going to cry that they didn't make it in since Nintendo don't own the rights to him, but if they do that's just a great bonus
But the characters that I wanted that aren't going to make it in at all due to Assist Trophies, Spirits, and Mii Costumes are: Rex & Pyra, Ashley, Bomberman), Isaac, Skull Kid, an ARMS rep, Takamaru, Chibi Robo, Saki, Bandana Waddle Dee, Wonderful 101, Hades, Decidueye, Elma, Shadow, Shantae, and Shovel Knight.
Now I don't believe that any of these characters had their spot stolen, but I do know that these characters just aren't getting in at all. I don't have any characters that I really want at this point that I think are slightly possible. All my favorites are just dead, and I see other fan favorite characters like Dixie Kong, Waluigi, Krystal, Paper Mario, and Rayman getting deconfirmed as well. Not everyone can make, but I would always appreciate that other people's fan favorite characters get in; which is why I like that Banjo got in despite not liking Banjo at all. There's just nothing left for me any more, especially if the next wave of DLC are third party characters and Sakurai continue the trend of ignoring that fighter ballot. Let's all be honest, there weren't that many people asking for Joker and Terry since nobody thought that was possible.