Well in a way, Fire Emblem was made big because of Smash. So the game having more Fire Emblem characters could be a testimony to that. Also, I don't think there's really too many Fire Emblem characters.
Marth and Ike have all the reason to stay of course, Roy got back because of him being immensively popular (even more popular than Isaac, that's saying quite a lot) and being a veteran, Lucina was a cool extra who is basically the second face of the franchise and easily the most promoted Fire Emblem character since Ike, Robin uses unique Fire Emblem-specific mechanics and represents the magic and tactical aspects of the franchise, Corrin is a odd one yet unique and represents the dragon's roles in Fire Emblem and even lances (if ever so slightly and even if Corrin actually never used a lance) and Chrom is just a extra character that remained popular and relevant over time. Awakening is kind of overrepresented, but it's the turning point of the franchise. It was the revival game and probably overall the most popular game by casuals.
Zelda also has overrepresentation of Ocarina of Time characters in a way, Fire Emblem Awakening and Zelda Ocarina of Time got exactly the same amount of characters. Fire Emblem Awakening has
and Ocarina of Time has
.
I actually wouldn't mind another Fire Emblem newcomer for DLC. And to be honest, I think a Fire Emblem DLC character is the biggest bet for a Nintendo-owned newcomer. Unless of course a new Zelda comes around, and it's as ambitious as a project as Breath of the Wild.. which I doubt, because such a game would probably have been showcased already.
We have to just patiently wait this one out unfortunately. Each Fire Emblem character in Smash, despite often only appearing as main character once, probably has a overall more important role to Fire Emblem than Impa currently has for Zelda. Zelda doesn't have significant one-offs that are main characters, the main characters are always Link and Zelda. Ganondorf doesn't even show up regulary anymore. Impa has too many inconsistent roles unfortunately. They could've easily made her a Echo. And I still don't get why they would favor Dark Samus over Impa honestly, if Ridley is already there and way more popular... I also think Impa would be more recognised as Zelda enjoys way more popularity than Metroid, and Impa is sure to return to Zelda, whereas Dark Samus is most likely not... So yeah, odd choice. But that might mean that Sakurai thinks Impa is capable of more.
Anyway, we've been screwed over twice now. Which is still not as bad as say,
or
or Isaac... But still pretty bad.
In retrospect, I would've prefered Impa being one of the last final newcomers of Smash 4 instead of them brining Dr.Mario back. Dr.Mario would've returned in Ultimate anyway because "Everyone Is Here". And Sheik was at her best in Smash 4. Daisy was also definitely not needed, especially cause
happened in the end as a unique Mario newcomer.
Talking about this definitely doesn't make it better tho... Maybe that's why I was absent here for so long.