the only new thing is the building called Military Doctrine. It will be different for the different cultures. If you leave the native doctrine (or build it) - you'll have the AOR units of the region. If you build your own - you have your units (based on the level of the four building levels). I just need to see again the "or" description in the building requirement block, so that you can build the doctrine ether for yourself or for the local tribes.
You want AOR units - pay the price. Leave the locals on their ways and they will rebel. Assimilate them - and you won't have warbands - you'll have legions instead (or the reverse if you are the barbarian).
Very,very nice idea. If you want it,so be it !

better aiming ballistas/scorpions/repeating ballistas.
- Yes

government buildings should give a pop-growth penalty, so that you don't grow from 2000 pop to 24 000 in a few turns
- yes

at least some law buildings, to keep the public order normal in the late-game.
-Maybe, give the bonus to law to the barracks ? It makes sense,because the higher the rank of barracks the more order will be ingame. Traders could give happyness bonuse because people are happy that they have verious things to buy or sell- ?

thracian legionaries! (post-marian)
- explain a bit. By the way we will have legions like roma surrectum after the marian reforms.

No crazy roman ships!
-explain a bit as I don't understand.

game-play temple balance.
-explain a bit as I don't understand.