I guess I would love some combination of both. It's really fun to see the same character with a varied number of personalities and/or physical features (slug-like, half-android, etc...) but having the multiple Spider-Men as well as all those different Lokis was super god damn fun.
If I had to absolutely choose one or the other, I guess I'd have them different just because that really opens up the potential to the point where the imagination is the only limit.
I think it would be interesting to have our version be the non-standard more often. Like Miles is a unique Spider-Man, where most are Peter. Pavitr has a crisis in the comics because of it.
Like what if most Lokis were alligators? Or most were legit Frost Giants and he was weird for being human-looking.
Most Lokis being alligators would be hilarious. Have a council of Lokis and the few humans we've seen are confused to see hundreds of alligators. Maybe a few crocodiles mixed in