While I am someone who makes as many player characters as possible in the games, whether it's 4 in the earlier games or 8 in New Horizons, I would much prefer for them to bring back the 15 villager allowance from the GameCube days. 10 villagers just feels too limited and, both in New Leaf and New Horizons, there are some villagers I've wanted to have as residents of my towns/island that simply didn't make the cut due to the limit.
The 8 player characters on the Switch are admittedly nice for someone like me, between making the island feel more lived in, letting me come up with characters with personalities and limited backstories, allowing for more opportunities to design homes (though that's unfortunately not up to snuff compared to the previous games due to the small room sizes in New Horizons) and granting me more storage space. However, I realize that I'm not really the average player; most people are probably only making one character for themself and maybe have extra characters in their town/island from family members or friends. Though, certainly, some subset of the playerbase probably makes multiple characters for the same, or other, reasons I stated.
It's a shame that we haven't been able to have 15 villagers since the GameCube game. Maybe they don't want more than 10 nowadays since it would lead to more dialogue repeating, which would draw attention and criticism. I mean, there's already criticism at the current level, so more villagers would just make it more apparent. I don't know. Whatever the case, I wish they'd allow us to have more villagers in future games.