Hellenic Native Phalanxes ans such

[XSamatan]

Not true!
Government type defines the possible level of both factional and regional barracks. The type of factional and regional barracks is the same under any kind of government, only the possible level for both varies.

Even though barracks building possibilities should be determined by government types, maybe it is not adjusted dynamically. Perhaps you can:
Build Type-IV, build regional barracks up to MIC level 5 -> get a lot of foreign units.
THEN
Destroy Type-IV, build pacification, build Type-I, build factional barracks up to MIC level 5 -> get a lot of factional units.
Thus getting the best of two worlds.

That is what I meant to say. Building a lvl 4-gov and upgrading it to max allows elite units to be recruited, then destroy gov and build lvl 2, as an example, and now building max own barracks is possible.

Spoiler Alert, click show to read: 

I gpt this from a thread I do not find now, but I will search it.

There was something said that you can upgrade a local barrack to lvl 5 if you just have the lvl 4-gov type at the first stage of the barracks and you could destroy the gov and rebuild it

XSamatan