Tips for choosing faction post patch 15

[Slaists]

I decided to start two campaigns - GC with Bactria and IA as Anthony. The starting position of Bactria is interesting for me, since my Iceni didn't make it so far and the last time I played in this region was as Sassanids in Barbarian Invasion.
Also Slaists convinced me to give IA a try - just sounded good and it seems the gameplay is different enough to the GC to give it a try. I haven't bought the AddOns, so there might be something new in it for me.
Still want to see how the original vanilla game plays out after the last changes, so there I am

If you don't have all the add-ons, some Roman auxiliaries might be missing. For one, without the raiders pack, Illyrian and Dacian auxilia is probably not available; at least their best units.

p.s. If you play as Anthony, Syrian armored archer auxilia is a God-sent unit to fight the pesky horse archers and skirmishers in the East. Don't under-estimate regular auxilia spears too. They're affordable and have great armor. I used them as a disposable screen to shield the archers while the latter annihilated horse skirmishers. Just a few legionaries in those Eastern Roman armies to kill the occasional Eastern spearmen unit.