Unfortuantely, I believe that military home city shipments actually are harming the game more than help. The problem is that they can be played instantly without any necessary prerequisites.
When you look at a typical persons deck now adays, it contains many fortress age military shipments. People fast fortress, and then use the fortress age military shipments to instantly get a very large very balanced army. The peasants gather just enough wood to build houses to keep the military shipments coming.
Heck, you can even examine your opponents deck from the near beginning of the game. You know exactly which shipments they are going to send in age 3. It does not matter. There is no way to counter other than to follow suit yourself.
Playing age 3 military cards has the following advantage:
1) Instant military
2) Well rounded military
3) No building prequisites.
If you don't play military shipments yourself, you are forced to build 3 buildings (barracks, stable, artillery) that totals over 1000 wood.
The fact that no military building or research is required to capitalize on aging up makes aging way too beneficial. An opponent can fast fortress and instantly gain the benefits of all the units available at that age. Heck, a few fortress units are often thrown in as a bonus just for aging. How can you NOT age and possibly win?
I think a solution should require that people build the corresponding military building before sending military shipments. If you want 2 falconets, gotta spend 350 wood on the artilery. It's so unfair that most civs can get such a well rounded army without this initial investment.
There should also be a building prerequisite for aging. This way, a person who was aging would have to invest in buildings like everyone else.