I don't want to stretch too hard in regards to squeezing characters into an alt role, so I like the idea of variants a bit better. Perhaps it brings up a little sub-menu of variants when you select the main fight on the UI, and then you can choose the variant's alts after you choose them.
In regards to Fire Emblem, the major archetypes that I think would be reasonable would be:
- Lord/Sword - Y'know, the Marth. Has a reasonably-sized sword. We're already familiar with these guys
- Myrmidon - Really fast swordfighters who usually have a katana, like Lyn. Probably has some quickdraw mechanics. Truth be told it's wierd that Sephiroth is the only katana fighter we have because katanas are pretty popular.
- Heavy Sword - More aggressive swordfighters like Ike. I suppose we could work in Chrom or Smash Roy (FE Roy is closer to Marth) as a variant with a smaller but faster sword
- Axe - Someone like Edelgard or Hector. They could be merged into the Heavy Sword category since they're both about big heavy weapons, but it might be a bit of a stretch
- Cavalier - Horseback riders; Sigurd's the main "horse lord," but it could probably include supporting characters like Frederick too. I'd imagine they'd lean more towards lances, though I suppose you could make a sword work over some of the movements
- Pegasus Knights - Also ride a horse and also default to lances, but their horses fly. I suppose you could work out a unique moveset, but it would work just as well to put them over a Cavalier and add some extra aerial moves and mobility
- Soldier - Lance-using infantry. The little stabby guy. This I'm kinda iffy on, because lances are the usual mook's weapon, but I'm not sure how many Soldier-type characters you could use. The most Soldier-like main character would be Ephraim; Timerra's basically a Soldier, and I guess pre-timeskip Dmitri could be squeezed in there, but I think he's better known for being a barbarian with what's basically a glaive, and that wouldn't fit very well.
or we could just have a generic soldier mook wondering how the hell he got here
- Magic User - In FE, the magic users are usually split between elemental Mages, Dark Mages, and Priests, but the former two could easily be merged together and the latter is geared more towards a support role; A full healer would be best as an Assist Trophy, and more offensive white magic would just be a spellcaster anyways. Micaiah's the purest magic lord, but there's a good few popular regular name units that could work too, like Lysithia and Nino. Celica and Robin are an odd case, because they use both swords and magic, and that might make things tricky unless we heavily downplay the swords
- Manakete - Y'know, the little girl who becomes a big dragon. Tiki's a no-brainer because she's shown up in multiple games. Corrin is a Manakete, but they seem to use the sword more often, and most spinoff appearances tend to manifest the shapeshifting as drill/jaw-hands that are completely different from the usual Manakete fare.
There's also Archers and Beast Units, but it feels like there aren't many popular Archers beyond Claude, and and Beast Units are a recent archetype who seem to change what species is used every game - Tellius has cats and birds, Awakening has rabbits, and Fates uses canines - So I don't think they're very Echo-able.
Might cut out a couple archetypes if it's a smaller roster, but yeah. That's about how I'd try to manage the FE representation.
Yeah, I'm viewing this through the lens of a soft reboot. Honestly, half the reason Fire Emblem got so many swordfighter is just because it has a rotating cast and probably would've rotated through the characters anyways; If Ultimate hadn't been an EVERYONE IS HERE situation, I'd imagine they'd have dropped Corrin and either/both Lucina and Roy, which would bring the lineup down to just Marth, Ike, Robin, maybe an Echo, and then Byleth later down the line, at only 3-5 fighters. Personally I think the hangups over the swordfighters is a bit overblown, but still, I feel like rewinding and covering more archetypes and weapon classes would be better representation for the series.