"Unnecessary" is a bit subjective here, but I've got four candidates:



NOTE: I don't actually hate any of these characters. This is just fun inclusion analysis for time-killing purposes.
-Dr. Mario is just regular Mario in a different outfit. This is more egregious than it should be as every other clone is at least a different character. Additionally, references to his home series essentially don't exist beyond megavitamins and music. Melee didn't have many options for characters, and he's a great example of this.
-Pichu, as mentioned by
Good Guy Giygas
above me, is mostly a joke character. No new content, no new abilities, just a worse clone.
-Dark Pit was already on shaky ground in Sm4sh. The reason he's a clone? "He can't use the Sacred Treasures." This feels like a bit of an excuse, but I tolerate it. But then in Ultimate, Pit's final smash was arbitrarily changed again. So now the one reason for Dark Pit being a clone no longer exists, therefore he's extra pointless! That, and his differences from Pit are trivial at best. At least the Echo Fighter concept
kinda justify his presence now.
-Corrin is odd, mostly since he's unique. As a promotional character first and foremost, I object to him already. But the fact that he originates from Fire Emblem of all places, that sucks even more. I do like Corrin's moves, but their series was already experiencing an uptick in sales. Did it
really need more promotion?
Overall, Sakurai usually makes good judgments on characters to add. Not all of them are winners, though. I was inclined to put Roy, Lucina, and Chrom on this list, but I don't know, they didn't feel as unnecessary to me. Roy's promotion, while still promotion, was a tad more justifiable at the time. Lucina and Chrom, as clones, offer more differences from their progenitors than the above-mentioned clones.