MUCH much much much M U C H heavier focus on making the military a MEANS of education rather than a replacement for it. Skill transferability should be more important than just paying for college because in a place where college isn't kept deliberately expensive to drive recruitment rates (perverse incentive, anyone?) it's far less relevant and in either case it means you start behind your peers.

For example: A friend of mine used to work a really high level tech job in the airforce. After getting out they ended up as a cleaner cause the certs didn't transfer. I think there should be a sort of mustering out test where the parts of your job that aren't classified are tested for which can then work as either an official college diploma or at least an entry test. Have pay grades work analogous to credits if you're worried about people leaving too early.

In general robust transfer programs would help a ton. If you had a solid pipeline from the military into another government branch it would not only help veterans but also the bureaucracy since people used to working fast would be quite beneficial in those positions.

Finally, make it easier for NCOs to commission and advance.