Banjo & Kazooie (oddly enough) are my number one choice (maybe second as well?) for Ultimate's third party newcomer.
While as a kid I played my dad's NES and SNES, the N64 was a Christmas gift to me in 1996, and was the first console that was truly mine. There was Mario. But right after him was Banjo & Kazooie. I really enjoyed the style of gameplay, the charming and sarcastic humor, the wide variety of cooky characters. And, as a kid, it was amazing to play. Unlike Mario 64, when you collected your prize--you could continue playing in the world! Novel. It really created a seamless experience to the quirky and legendary soundtrack of Grant Kirkhope. Every step of the way, you were learning new moves, opening up the freedom of movement. The first time you jumped off the flight pad and soared wherever you wanted to go was exhilarating. No time limits like Mario's wing cap. You could fly as much as you wanted so long as you had enough feathers. And that was level 2. The game got progressively harder as you played, to the point I got to Rusty Bucket Bay and genuinely got frustrated. Replaying the level over and over again, being exceptionally challenged like I never had before. It actually took me a couple years before going back to it, and going into the last world was both a nostalgic and novel experience, all the way to the final boss that tested everything that I knew.
It was critically and financially successful, as well as its sequel, Banjo-Tooie, which was larger, more complex and was able to add on to the freedom of movement you had from the first one. Banjo-Kazooie is one of the best games on the N64, and solidified Banjo & Kazooie as Nintendo icons. Until something horrible happened--Microsoft bought off Rare, made ports for its console, and remained dormant until they came out with Nuts & Bolts, which turned this charming platformer into a make-a-car game. It was confusing, lacking any of the personality of the original games, and I bailed out after the first few segments of the first world. Despite this, Nuts and Bolts has its fans, even people who had never played the original games, and really speaks to the power of the characters themselves.
Had the Rare buyout not been starting during the development of Melee, Banjo & Kazooie would have certainly been in. They were Nintendo icons, one of the best of the platforming and collect-a-thon genres of that time. And their game is all about learning new moves--rolling, pecking at baddies with Kazooie, charging with Kazooie's beak. Kazooie's flight allows for a variety of movement options, as well as shooting eggs make Banjo & Kazooie a dynamic figher. Not to mention all the individual moves you learn in Tooie, including swinging Banjo's backpack and swiping at foes with Kazooie's wings. There are so many ways you could take the character. A two-in-one fighter, that could either remain standalone similar to the Ice Climbers, or switched around like Pokemon Trainer, with a lot of moves that are quite similar to the Duck Hunt dog--perhaps inspired? And while they may share similarities with these fighters, their breadth of moves throughout the two games could make them a very unique fighter on their own.
And many of the elements of the games fit nicely into Smash. A variety of worlds that could become stages, including the iconic Spiral Mountain, or Grunty's Castle. Mumbo Jumbo would make an excellent assist trophy--temporarily turning opponents into useless washing machine allowing a full on assault. Or turning Banjo-Kazooie into a T-Rex. Gruntilda would be a fantastic stage boss, a unique character in her own right, flying around on her broomstick, throwing fireballs, and to attack her you hit her in her bulbous butt (reminds me of a 30 minute promotional video that liked to emphasize that). And her Rhymes could be this game's Snake's Codecs and Palutena's Guidance, snarky comments on the other Smash characters in silly rhymes. Or Brentilda, her sister, who could dish out all the dirty secrets on Smash characters. The stages and characters would make a great addition to Smash, as well as it's amazing soundtrack, composed by Grant Kirkhope.
All in all, Banjo & Kazooie has been one of the biggest missed opportunities. While I never had a Gamecube to speculate in the Melee days, while playing Brawl I was incredibly aware of their absence. Mario, Donkey Kong, Link, Pikachu, Bowser, Zelda. Even Sonic? It seems like a certain Nintendo character's missing. And it's not entirely a pipe dream, as
Phil Spencer, head of Xbox, has expressed his interest in seeing Banjo & Kazooie in Smash, the same time the ballot was going on and Banjo & Kazooie's popularity were fairly strong, especially among third parties. To me, while there are characters I'd like in Smash, and I in no ways want to demean other character choices that to other's are just as worthy given their relationship to their favorite characters, for me, at least, Banjo & Kazooie are the missing piece, and would complete the roster given their legacy with Nintendo, their moves, characters, music, the nostalgia, as well as the potential to work with a rival, and in my mind, correct a big mistake in Nintendo's history. Banjo & Kazooie may have different owners, but they will always remain Nintendo characters in my heart, and they deserve to come back home where they belong.