One thing that I hope to see is a heavy expansion of being a mercenary, bounty hunter, and the whole deal of being on sort of secret missions, such as spying, secret imprisonment (instead of assassinating since lords can't be killed), general kidnapping for various purposes, etc.
Maybe even have a thing of advancing ages, for example the game starts Native-ly, then goes towards something that looks like WFAS, and eventually, NW. Of course, these options can be configured and disabled, for example maybe you wanna start in WFAS-ish era, and maybe stay there, or maybe be capable of skipping WFAS era and going straight from Native to NW.
I really hope that the dev team is actually looking at and considering all these suggestions, taking looks at mods and consider having improvements that they add, etc. That's one thing that makes a great dev company.