Dark Souls 3 has a pretty cool system for something like this, with the password co-op. It'd scale you down to the host.

Unfortunately, I don't really see this game getting a system like that, given how the game is set up to be more like "joining a friend on their save", and the release date is getting pretty close.

Maybe we'll be able to hire people like we could in the first game? That way if a friend joins you on an on-going save, they could make a hireling, and you customize the race/looks/name/stats/etc.

At the very least, it would be nice if we could save our origin/race/customization options as player presets, so we don't have to re-create the same characters repeatedly.