As an individual militia won't even get near the amount of combat experience our mercs get, we could alter the speed with which they earn stats.

We train green militia just like before. Once new ones are created, we tie a new MILITIA to them. Stats are randomized within a certain range for each stat. Thus some of them might be more promising than others.

People love deciding on skills and such. For this reason, we can select which traits a militia has - we choose for them. If you have a bunch of rookies and a bunch of shotguns, it would be smart to assign the 'Ranger' trait to some of them, no?
Each militia rank grants additional traits (that's also how it works currently). So a green militia can only have 1 trait, an elite can have 3.

Certain traits are only available on higher ranks - so 'Deputy 1' is only open to veterans, and 'Deputy 2' requires 'Deputy 1' and is only available to elites.

'Doctor' could be a viable trait for militia now. We could allow them to be medics, New_feature: AI medics & officers. Perhaps militia doctors should need special training, and should cost even more? Special care should be taken as to not let this be exploitable - merc doctors must not be replacable.

If we do not play with 'equip militia', what items do they get? Currently the traits are selected fitting to the items they get, this is no longer possible. We'd thus need new tables that determine what traits grant what items (so that Rangers would get either shotguns or rifles etc.).

If we do play with 'equip militia', they will pick up gear from the sector if they don't have any. Using the above described, yet-to-code interface, we need to be able to add and remove items to them - we can then finetune their inventory to an absurd degree. How finetuned depends on how much time one wants to waste on this, really.

A problem in this case is ammunition. Even if we allow them to restock after battle, it could happen that a gun runs dry. We then either need to warn the player of this, or have them drop the gun and select a new one - but this could then be an override to the player specifically giving them that gun.

The militia redistribution in cities won't be useable any more. We need to come up with an easy way to order masses of individuals to different sectors - easy to use for lots of people, while still allowing to select what each individual does.

When we order a squad of militia to move, we need to be able to select who from a sector moves and who stays behind - selecting all of them is not good enough.