On a serious talk, what 3rd Party DLC characters would you rank on a Joker-tier level in terms of pipe dream/shock/impossible value?
Hmmm. Phoenix Wright certainly comes to mind. He's got a fanbase, but a lot of people previously didn't believe he'd make it into a fighting game. Heck, even after UMVC3 and PxZ2, people have still doubted him, since he's kind of a Capcom underdog, despite having been one of the lucky ones who hasn't suffered Capcom's worst.......well not entirely, but I digress. The point is that, like Joker, Phoenix has a fanbase, moveset potential,
Sakurai has spoken positively of Ace Attorney, and the lawyer does provide a unique gameplay that Sakurai would be attracted to.
Really hoping that meeting that Takumi and Sakurai had in 2016 is hinting at what it seems to be.
Anyway, aside from Phoenix Wright, we have Master Chief. Seems a bit of pipe dream, but he has some Nintendo certification via Minecraft. Out of the main 3 (Steve, MC and Banjo) he's the least expected, but that doesn't mean he has a small fanbase. Microsoft haven't really been selling people keenly on the idea of Xbox One since well, it's lacking in exclusives (you can play just about all their games on PC if you wish), so it's not outside of reason to suggest that plenty of Halo fans are multiplatform owners. And let me tell you, Halo fans are HUNGRY for something good featuring Master Chief after the likes of Halo 5.
NiGHTS would absolutely shatter expectations.
Twintelle has the whole spirits thing and the idea that we're not getting an ARMS rep, or another 1st party rep at that, going against her. So she'd be a delightful shock that no one really sees coming. She's got the popularity to back the surprise factor too.
An Undertale rep that isn't Sans. Look, don't get me wrong, Sans is neat, but as a fighter...eh, character wise it wouldn't really fit. And since he's the one people are expecting in droves. Yeah, Undyne, Frisk, or heck, even Papyrus would fit the bill for that.