Wow I really appreciate your suggestion and how much work you put into it!
The class style you are suggesting is actually pretty much how it works in the background already. And I am also planning to give each class custom outfits, not just helmets even. You will also be able to customize which weapons each class is able to use as well as their health and how often they appear on each side. Mods will also be able to add new outfits/armor.
The special behaviors you suggested like moving in groups of 3 or focusing on killing rather than the objective I won't do for now, but there will certainly be updates to how they behave in the future.
A longbow and axes will also come to the game and the crossbow is just around the corner
I also have to say your drawing looks awesome, it is quite similar to what I have in mind visually for the helmets. You will see once they're in the game for the Steam early access version!
And of course, more settings, playing on the red team, new game modes and maps will come as well. Slow motion probably too
Thank you!