People say it's the clones that are the biggest issue people have. But that's the opposite, really. I mean, the most drastic reactions were to who? Not Chrom or Roy or Lucina. People shrugged those off. They were to Corrin and Byleth, original characters. And it wasn't on the basis of them being "bad" characters, it was on the basis of volume: "another FE character".
So if you mean to tell me getting Corrin and Byleth, and then three more original characters would've resulted in less blowback, I'm sorry, but I just can't get behind that idea. It's because, as I'm saying, the root of the issue, whether it's articulated as such or not, is that of quantity.
I mean, half of the entire Zelda series are clones or semi-clones, and yet you don't see people griping about the series' overrepresentation. People might not want another Link but they certainly want another Zelda character. Because again, it's about proportion. Zelda isn't perceived as punching above its weight. Even though it has six characters, some think that's underselling the series.
That's primarily because Roy is seen as 'Smash Royalty' due to being amongst the first FE characters included and being from Melee. Lucina was lamented as being a 'Clone' and people demanded she be made a costume. Chrom was only 'okay' to people because of being an Echo..but there were still 'oh, another FE..'
The fact that people complain about characters with original movesets is ludicrous to me.
Zelda's fine to me. It has more than enough representation through characters, stages, music, items, etc..playable characters aren't going to happen much for the series due to how its set up..I just don't think Sakurai wants to include one-offs if he doesn't have to. Fire Emblem is a unique case due to its revolving roster while Zelda's stays relatively the same with a few standalones.
The reason people don't complain about Zelda, or Mario & Pokémon, not having enough and Fire Emblem having too many is due to their misguided belief that more popular series are more 'deserving' of newcomers.
Fire Emblem has noteworthy characters, as do other series. But other series' noteworthy characters seem to be included with much less consistency, despite still being noteworthy. You've also got to ask yourself if starring in one game is actually any more noteworthy than having a recurring role in five, or ten, or twenty? I'd say it depends on the notoriety of the series itself.
It's not like we've got to the point where all the noteworthy characters from every other series have been thoroughly wrung out and included, yet due to FE's size, its stable keeps providing. That, hypothetically, could come at some point, and at that point invoking the size of FE's cast makes sense, but since we're not there yet, shouldn't noteworthy characters come from as equal a plane as possible?
Like I said above, Fire Emblem is a special case due to it having a new roster each game, meaning to represent the newest entry in what is honestly one of Nintendo's most popular and growing franchise is to include a new character. Other series, like Zelda or Mario, can just include a new costume or move to represent the newest entry in the title. For example, Link represents Breath of the Wild through his new costumes and revamped moveset while Mario represents Odyssey through his Wedding Costume and having Cappy added to his Up Special and Taunt..Fire Emblem, on the other hand, can't represent its newest entry by a simple costume swap or a new move. The same can be said for Kirby..just being Kirby represents the newest Kirby game since, well, he's the main character.
The other big, popular series all have their main, important characters included..so its really ending up becoming a 'well..just throw in this side-character'. I mean, I won't complain, I still want Dixie Kong or Princess Hilda, but that is what it is.