On the earlier topic of most controversial character inclusions in Smash, Wolf was up there with ROB in Brawl. Casuals reacted very negatively to him with the thought of "Brawl's final secret newcomer is JUST ANOTHER FOX CLONE?!", with most writing him off as a Fox clone after a surface-level look at his special moves. Even near the end of Brawl's life I saw some casual players still complaining about his addition and even wanting him cut to "get rid of the clones". There was also the whole Wolf vs. Krystal conflict in the Brawl days, and the large amount of Krystal fans reacted very negatively to Wolf getting in over her. Wolf's reception among hardcore players was a lot more positive though, and others grown to view him more positively as time went on after discovering he wasn't the clone they thought he was and finding him fun to play.
Then there's Lucario under the tier of ROB and Wolf in Brawl, with the whole "Lucario replaced Mewtwo!" bull****, which there are still some people who believe it to this day despite Mewtwo being in Smash 4 alongside Lucario, no excuse for thinking they're any sort of clones of each other, and it being common knowledge that Mewtwo was planned in Brawl. Funny thing is if any characters in Brawl were to blame for Mewtwo getting cut, it was either Jigglypuff (being the closest thing to Mewtwo's direct competition for a slot as they were both gen 1 pokemon veterans that were low priority) or Pokemon Trainer (as he brought three unique gen 1 pokemon newcomers onto the playable roster and would thus be a lot more responsible for pushing Mewtwo to low priority). Greninja in Smash 4 also got the "he replaced Mewtwo!" slag too, with a lot of people thinking Greninja's reveal trailer was going to be for Mewtwo, though it profilerated nowhere near as severely as Lucario.