Not releasing Mother and Mother in he USA, questionable characters in Smash, cutting characters in Smash, and making Black and White 2 (could of used a remake instead)
The reason Mother 3 never saw American release was because Earthbound itself sold
horrendously badly in the West, though. Had it at least done decently, Mother 3 may have been localized.
As for Black 2 and White 2, the problem there is that they had already covered the first two generations, and the third generation wasn't quite old enough to need remakes at that time. They were literally unable to remake any other games, so going the sequel route was really their only other option.
The reason the Ice Climbers were cut was because the 3DS was having trouble with them, and Sakurai wanted to keep both versions consistent to keep the functionality of character transferring stable.
Lucas was no longer relevant, having starred in one Japan-only GBA title released half a decade ago at this point, so he was high on the chopping block. Wolf was probably cut due to time constraints more than anything else.
And with the Pokemon roster already at 5 (
6 when Mewtwo is available), keeping Squirtle, Pichu and Ivysaur in the roster would have just caused an
even bigger complaint of Pokemon being overrepresented in Smash. Adding every Pokemon character we've had into Smash gives us a total of
9 characters from the Pokemon universe, compared to Star Fox's 3, Mario's 14 (counting the Koopalings, Yoshi, Wario and Dr. Mario), Donkey Kong's 2, Kirby and Kid Icarus' 3 and Metroid's 1 (since Samus and Zero-Suit are the same person).
And I think that we got too much in the way of Kid Icarus' representation this time, personally;
especially considering how historically insignificant the series is in comparison to other franchises with less in the way of playable representation.
The only newcomers that
really should be playable at this point are Ridley and King K.Rool, especially since their series A) have very little in the way of fighters to begin with and B) are historically significant to a
titanically more important degree than Kid Icarus or Kirby are;
Donkey Kong Country was a pioneer for the SNES' graphical ability, and
Metroid, in addition to being produced by Gunpei Yokoi, sported one of the most shocking video game reveals
of all time and paved the way for female protagonists in video games to become a thing. Kid Icarus was a dead franchise that only recently got a new game and somehow has enough notability to not only get
three playable characters, one of which is an almost-identical clone, but also an Assist Trophy, two stages and a large amount of Smash Run representation.
But hey, if Dark Pit can be his own character, why not make Dark Link, Mr. L and Shadow Mario their own unique fighters, since we
obviously don't have enough representation of those two franchises?
incaseyoucan'ttellimprettysouraboutdarkpitbeingplayable