Steve,
I've been thinking about the reality of placing a division of ground troops, or more, on a desolate moon colony as a garrison for years on end, and when they are finally moved to a forward area where they are needed for combat, their readiness is pretty much good to go.
To that end, how about some sort of supply consumable used by ground forces on planets that do not have colony populations above, say, five million. This would be used to replenish readiness of a unit as it uses parts, ammo, and people in it's daily operations. Say a division is deployed with the necessary equipment to operate for six months, but after that time it's readiness drops until it is no longer combat effective. The supplies would be taken to the divisions by freighters, or troop transports, and would include the ability to provide replacements for soldiers lost due to combat, supplies used, etc. They would be able to be stockpiled, to allow for long periods when the supplies may not be delivered (planetary blockade) and slowly be used up for every day, or five day, beyond six months that the unit is deployed.
The real goal would be to provide a realistic approach to battle losses on a hostile planet and their subsequent replacement, bringing the unit's readiness back up after a series of battles. This would also make using troops to address unrest on distant colonies much more expensive and require constant supply runs for the garrisons of conquered planets.
I know with all the other changes going into 4.1 this is far from being on the burner, let alone out of the box, but just a thought for future versions.
Adam.