AOR Units - What purpose do they serve?

[Summary]

As the title says, I am a bit baffled as to the purpose of AOR units. It seems they are lackluster in terms of combat ability in comparison to regular troops. Why would I prefer more expensive AOR units to cheaper faction units, especially when the former has lower stats? I am sure there must be a reason I am overlooking, anyone with insight care to share please, much appreciated.

[KAM 2150]

They are cheaper than factional units and draw for foreigner population class, meaning you can have a lot of them, especially when you congquer city early on when your own population is building up. There are regions with more exceptional AoR units.

[Basilius]

For the record, I think DEI should have more "exceptional" AOR units, in addition to the abundance of low-quality levy troops. Right now most AOR units are not worth recruiting, which is a waste.

[Dresden]

A lot of people use AOR units as local reinforcing armies as they can replenish immediately from foreigner populations.

[Garbad]

AOR troops are great early game, but lacking endgame. I agree that there should be a way to upgrade them or some elite AOR units.

[Caledoni]

I really like the AOR unit system as it is. It adds uncomplicated diversity to armies especially in the early game and also can help with invasion momentum. My only criticism is that some of the units seem to disappear with Reforms or building upgrades (can't remember which one was the cause but I could no longer recruit Appolian Inf.)

[struckat]

I like the AOR system as it is. Sure a few more elite units would be fun, if not accurate.
The way it is now makes sense.

[Irishmafia2020]

There are some very useful AOR units in the game that fill gaps in the regular faction troop rosters. There are areas I tend to conquer in-game simply because I value the troops that are available in those regions. Rome, for example, can use better cavalry. Egypt needs to find a source of heavy infantry, as do many Eastern factions. I love the AOR system, and I use some house rules to maximize the "fun" factor that they allow.

[Caledoni]

Playing as Macedon now. Had forgotten how amazing Agrianian Axemen are

[skillfultree]

I love going around recruiting various AOR and mashing a weird army together. or having a greek army made up entirely of various AOR greeks.