Its sad that FE's over representation is the reason why fans are distasteful of other anime looking swordfighters like Hero from Dragon Quest during first impressions...
If I'm being perfectly honest, while FE exacerbates the issue, I don't think a smaller selection of FE characters would have significantly improved Hero's western reception or any character with an "anime" look.
There will always be exceptions of course,
, but generally speaking, any character without a huge hold in the west will be criticized by the west. It's the Goku problem or perk if you're an FF or KH character. Loads of people in the west dislike anime/anime style games but will swear by DBZ or Pokémon because it's among of the few they tried/were exposed to and it helps in DBZ's case that Toriyama's art is so distinct (Pokémon's got a pretty distinct look too actually and there's the benefit of you know, the Pokémon.)
I've no doubt that any series like Phantasy Star, Ys, Trails, Disgaea, Bravely, even Tales etc. would all get negative to mixed reception in the west.
As for the FE lineup itself, it's- difficult imo.
On the one hand, people complain about Marth clones, but Roy is a fan favorite among Smash players and both Chrom and Lucina are very popular and significant characters from one of the most popular and significant games in the series. And if the base character is there, there's little reason to
not include them again. If you're cutting characters not to save on dev time/costs and instead just to appease western fans who want to see "number go down" I don't really see the point. It's not like these characters/series don't have established and growing western audiences of their own either.
While I do think they're fun to play, Corrin really is the only one I see as having more genuinely going against them if they want to trim things down, and even then, that more than likely comes with a new FE character getting brought in anyway.