I'd suggest more multinational characters. It would fit today's age very well and appeal to a wider audience. The Los Illuminados Cult, the Majini, the J'avo, Alfred, Alexia and Excella proved that foreign accents and looks help give the RE universe a more wordy touch and helped the series develop very well from 4 onwards. I think RE7 was an exception to the rule, but then, the game was very narrowly confined, so it couldn't continue the diverse nature of people in the series.
Ideally I'd like the next main installment to take place in a more Northen region, say something like Maine, and have the story take place in a more sparsely populated town that's been infected by a virus during winter. It would be something entirely new in the series.
You could include a Canadian character speaking with a French Quebec accent.
So far, Resident Evil has avoided creating stereotypes. Depth is important to all the characters and for the series to continue, the people involved must be involved in something or other. Angles are important and everybody should play roles in them and make sure the story is formed with them. Like when Jill and Carlos were trying to escape Raccoon City and help anyone if they could, Nicholai was carrying out field research and experiments for Umbrella, eliminating his fellow unit members because they weren't in league with him. That presented an element of mystery and suspense that made a short game quite endearing.
You know I would much rather the next Resident Evil game continue with the mainstays. I wouldn't mind side characters or maybe a new character helping one of our already established heroes but as far as deviating from what's already been going on like Resident Evil 7 seemed to, I'll pass.
As for their hypothetical nationality, it doesn't really matter to me as long as they're a decent character and don't feel like a cheap add on for the sake of diversity.
+++ WARNING: The following post mentions something positive about Operation Raccoon City. If you are sensitive to the subject, please don't read any further. +++
So yeah. One of the things I like about ORC is that every character in the Wolfpack has a different nationality, and in most cases you can tell by their accents. What I like even more, however, is that it actually makes sense, but at the same time doesn't matter! Unlike the governement spec ops, who more or less have to be US Americans because they're patriots serving their country and all that, this Umbrella unit is compiled of criminals with the right talents to get the job done, never mind age, gender, or nationality. Visually, they may be a little harder to tell apart at first glance than, say, the S.T.A.R.S. members because of their black leather attire and hidden faces, but if you look at their profiles, you'll quickly discover that we've never had such a diverse cast of characters within one RE game. We have a mother who's basically only in it to provide for her children, a horrible doctor who likes to cause pain, a school bully with an artificial leg turned into an explosives expert, etc. And now comes the twist: This would still be the case if you changed them all into Americans!
What I'm trying to say is: If you need to rely on different nationalities to convey to the audience that those characters are different from one another, you're doing something wrong. That's why I don't care what birth countries Capcom is going to slap on future characters - as long as they don't have personalities and back-stories that make them stand out from the rest, as long as they're as bland and boring as Ethan and Mia in RE7, wherever they come from isn't going to save them from the scrappy heap. So don't just stand there like J. K. Rowling, saying: "Look how inclusive I am with my Jewish / foreign / black / gay / trans / whatever characters you never even knew were in my stories because I just pulled them out of my behind for political correctness", because that's not going to make your game suck any less if it's bad, and it won't add to the believability of those characters either. If a character's nationality isn't somehow related to their personality (like they have a history of being bullied for it, or their home country has some specific rules and customs that explain their behaviour), it becomes nothing but an accessory. And everyone knows to only put on accessories once you're fully dressed.
This thread could use a less misleading title, by the way, I didn't come here until now because I thought it was going to be about something different.