One thing I've seen almost everyone do in here is assume this would take place in a vacuum, basically as if there was no other chance for any DLC characters. That's not the case, though...which is why I'd probably hold off on sacrificing anyone for several characters I want, because a lot of them have a pretty good chance of making it
without needing to go through all of this.
If I had the chance to add some long shots, though?
Sacrifice:





The bonus clones are the most expendable of them, since they'd probably be the least missed. Maybe they could still hang around as alts of their source characters like what the original plan was. The other two are just among the more expendable, from my view: Jiggs is just kind of
there nowadays, and Ryu is among those most likely to not stick around for the next game.
Add: Delphox
Well, no one said there wouldn't be bias involved. Mages tend to be really popular, and this one in particular could really stand out.
Sacrifice:





The Mii Fighters have their fans, but they also feel on the expendable side, and when they're less dynamic than most other characters, it'd be less of a loss in that regard. Meanwhile, Roy is still only a semi-clone with a divisive past who isn't well liked in his home series. Mewtwo would be controversial as hell...and yet, opinions have kind of soured on him as of late, with how lackluster he's been.
I'd only hope the character that joined in his stead would make up for it.
Add:
Absol
A fan favorite Pokémon with a
lot of unique abilities that'd lend toward a really interesting moveset. With attacks based on foreseeing disasters that then befall the stage a few seconds later, Absol could be a zoner/summoner completely unlike anything Smash has seen before. Shame it almost surely wouldn't happen otherwise, right?
And for those who'd cry "over-repped", Pokémon would end up with the same number of characters it currently has, and even have them better spread across the series' history instead of being so focused on its first games.
...Would I go through with it, though? To be honest,
probably not. Every character has their share of fans, and even though I want to think both of mine could become fan favorites, throwing out
five other ones
each for their sake would feel like I'm disregarding too many people.
Now if it was a one-to-one trade, on the other hand...