I will try to answer based on my current plans, taking into account that at the moment I'm busy with
another well-known mod and I need to get that one out the door first, before I can concentrate on RotE full time.
What are you going to do for the settlement walls - Every settlement will need to be reworked, meaning, I'll have to make them from scratch. I will get rid of all walls, any battle with walls is only going to take place insode fortresses which are outside the cities themselves. It is true that there are isolated cases of medieval towns still defended with the old fortifications however I think it is still more interesting to have open battles or city occupied by an army - with all the destruction and destabilization it involves - since MTW2 allows us to recreate detailed 18th century cities I am excited by the challenge.
Recruitment - Will be done with a building structure similar to NTW, I plan on remaking the building trees.
Battle mechanics - This is undoubtedly the hardest part to get right. I have done extensive research on how MTW2 handles ballistics and I've already set up a whole different version than the one available to the public. I will most likely release anotther custom battles only version to specifically test this new battle plan and see how people react before I finish the campaign, which will be realistically done by January 2018 at this point.