Take my responses with a grain of salt. The whole concept of who is the "Most Deserving Character that will never happen" is opinions covered by facts in the first place. Except Bomberman and Banjo. Seriously, nobody can argue with them. Eevee I definitely can definitely agree with. But I'm still iffy on Donkey Kong Jr. and Pichu, though.
Like, what is this in comparison to? Plenty of Pokemon that get more attention than Pichu within the Pokemon fandom (with Omanyte probably being the most popular unevolved Pokemon after Pikachu right now thanks to Twitch Plays Pokemon
), while Roy, Mewtwo, and Dr. Mario all seem to be the most popular lost Melee veterans. I just don't see what niche Pichu has right now beyond those that really loved playing as him in Melee (which, judging by how he's second to last in Melee's tierlist, I can't imagine too many people did). Aside from not having a successor, Pichu literally seems as deserving as Young Link to me. Jr. likewise isn't a popular DK character compared to Dixie, K. Rool, and Cranky, nor is he particularly a major icon of the NES era compared to Balloon Fighter and the Duck Hunt Dog (not even going into confirmed character games or third-parties like Kid Icarus, Punch Out, Mega Man, and Castlevania).
I get it if this list is based on your
opinion, but if it's based on the perception around others, I'd be much less prone to agreeing. Opinions I can't call wrong, but demographical claims like "most popular" make me want to see a source or something before I smile and nod to hearing Donkey Kong Jr. being one of the most popular NES characters. I've searched several online "Top Best"/"Most Popular"/"Best Selling" NES lists and I don't think I even found Donkey Kong Jr. once, actually...