It's also worth bringing up that certain characters are still just too hard to get, even for Sakurai. There's a lot of talk that Sora was the original choice for Sephiroth's spot, but Disney got in the way. We've already gotten Banjo and Steve, so more Microsoft (including Bethesda's Doomguy) might not be where Nintendo wants to take the series. There's also decently founded speculation that Byleth's moveset (slow weapons tactician with moves based around an axe, a sword, and a longbow) was originally made with a Monster Hunter rep in mind, and seeing as we had a Monster Hunter boss, Adventure Mode map, and Assist Trophy in base game, it makes sense that they simply lost negotiations for a Monster Hunter character. Steve took like 8 whole years to get into Smash Bros by himself!
Xenoblade is a modern first party franchise that people, including Sakurai, really seem to enjoy. I'm not the audience for this character personally, but with now 80 characters in the game, I ain't got nothing to complain about honestly. I'd love to see Master Chief or Crash or Rayman or Waluigi get into Smash, and I believe any character from a video game is fair game at this point. But some things just aren't gonna happen, and that's okay in my book. That's just my thoughts on it though, and I've been lucky enough to get most of my top picks in already over the years.
Also, talking about Pyra/Mythra as a character(s): this is our first brand new Switchable character since Pokemon Trainer in Brawl! That's crazy by itself.