It's kinda weird that Kat & Ana survived both Assist Trophy massacres. There's going to be 50+ Assist Trophies so we'll have to wait and see if they get promoted or not.
Since it keeps getting brought up, I may as well do my own analysis on the potential reception from the fanbase in the event that Kat & Ana got promoted.
While WarioWare's cast is a generally beloved one, Kat & Ana fall behind a bit as far as popularity goes as best as I can tell. When people discuss potential new Wario characters, along with the most popular Ashley I pretty much only see 9-Volt, Mona, Jimmy T. and the odd Captain Syrup brought up. Therefore, my first point is that
Kat & Ana are not considerably popular in their own series.
Kat & Ana also suffer from a similar problem that Ashley has; relative importance to their series. But unlike Ashley whose prominence has been steadily increasing, Kat & Ana have very much remained just another pair of members in the cast. The only thing they have over Ashley is seniority, and not only do I doubt the importance of that in the face of popularity but they also don't have any seniority over the other original WarioWare characters. My second point thus is
Kat & Ana are no more important than any other member of their cast.
They're also... some of the most lacking in moveset potential from the series. 9-Volt could incorperate various old-school Nintendo games and products into his moveset, Mona and Jimmy T. could just have plain goofy WarioWare fun, and Ashley has magic on her side, but... What would Kat & Ana be? Just Ice Climbers but with swords? They only fill a niche that has already been filled to a brim, and even if you look at them very charitably their gimmick is still already taken by the Ice Climbers. Third point then is
Kat & Ana would not be the most interesting/unique characters from their games.
And of course, they used to be Assist Trophies. There's a
lot of popular characters stuck in snowglobe hell, aside for the obvious Ashley. There's Alucard, Bomberman, Ghirahim, Gray Fox, Isaac, Isabelle, Knuckles, Krystal, Lyn, Magnus, Midna, Ray MK III, Rodin, the Sablé Prince, Saki Amamiya, Shadow, Shovel Knight, Skull Kid, Starfy, Sukapon, Takamaru, Tingle, Waluigi and finally Zero.
That's 25 different characters (counting Ashley), who all seem more popular than Kat & Ana from my experience. Even if you remove the 3rd-parties on the principle that they're in different leagues, that's still 17 characters who see more anticipation than Kat & Ana. My fourth and final point taken from this is
Kat & Ana are far from the most wanted characters who're stuck in Assist Trophy hell.
So, imagine the reaction to an AT who wasn't at all popular among them being promoted, and they aren't even the most popular, important or creative characters in their own series. Yeah...
WarioWare fans would be pissed that they aren't Ashley/9-Volt/Mona/Jimmy T. General Nintendo fans would be pissed that they got in before so many other great Nintendo characters. Sword haters would be pissed that
there's another god damn swordfighter character. Fans of Assist Trophy'd characters would be
incredibly pissed that Kat & Ana of all characters were among the first promoted.
I think Kat & Ana would stand a very good chance of becoming the most controversial pick in the series' history. They could make the reactions to R.O.B., Corrin and Bayonetta look tame and even joyful. I cannot imagine the developers being so completely ignorant of this. If they were at all smart, they would
never pick them to be among the first promoted.