Assuming there is a new WD game in development, and that it's not too late to make a suggestion...
First, I have to say that I didn't like WDL as much as I liked WD2. The reason I play open world game is not for the story or characters. I play these game to get immersed in a living breathing world where I can observe the world, interact with it and enjoy a world around me that keeps going regardless of what my character does.
WD2 was amazing to me, I still play it after 5+ years, and can't get enough. However, I got bored with WDL after a month. The Play-As-Anyone mechanic was an interesting idea, but I didn't like it.
In reality, if you watch 100 videos of WDL gameplay, 95% of the gamers will be using the same characters (spy, old person, Albion guard, beekeeper and a couple more). Most other characters are made boring intentionally to lead the gamer to pick the same characters from the marketing videos.
Once you pick a characters it doesn't mean much because you do the exact same things you do in any other open world game: walk, shoot, drive.
I much prefer WD2 which had an amazing living breathing world. I don't want to be the other people, I want the world around me be to be living breathing, and WDL was a huge letdown for me after WD2.
So here is my suggestion for the next game: Ubisoft should forget about the Play-As-Anyone thing, and go with something like Socialize-With-Anyone (I hate to use the word "socialize", but couldn't find another word). Meaning, any NPC can become related to your character - meet, help in a mission, interact, go out together, pick you up in car, pick them up in a car, date etc etc etc. This would make the most living breathing world. At some point you would have many contacts with different abilities and professions in your phone and you will be able to even get together with let's say up to 3 NPCs at the same time. Which can lead to interesting interactions (agreement/disagreement) between these NPCs. They will have actual daily routines based on their profession/personality and you will be able to observe anyone's routine in real time.