Ok, I have played 1 battle and here is some feedback.
First of all, I will attach a screenshot:
As you can see there, I have won a decisive victory, with a cheaper army.
That wouldn`t be anything special, but the thing is... Throughout the battle, I felt the AI isn`t giving me ANY challenge.
True, I didn`t really give the AI any units that are likely to pull of anything more then a frontal charge.
But still...
I flanked the AI units constantly, and effortlessly. I got both my slingers, then my Scutarii, and finally my cavalry behind their back.
Once I would charge in, or started pounding them with slingers, they would almost immediately break and flee.
In itself, this isn`t a bad mechanic, as it is fairly realistic. However, I have got the feeling the AI is at a problem here.
In all likeliness, the AI is too stupid to predict my flanking moves, and to counter them.
And when you combine that with your mechanics of breaking more easily when flanked, it allows the human player to beat the AI EXTREMELY easily.
I mean look at some of those numbers in the screenshot. The AI Triarii routed with 75% men left, and after killing only 20 something of my men. The AI Principes routed while killing less than 20 of my men on average...
Now, this is just 1 battle, and a custom one at that, so you might say we shouldn`t draw conclusions from that. And you are perhaps right, but this looks like bad omen...
Overall, I think further testing is needed, and possible recalibration of units, and especially their moral stats.
IMO, it is better to have somewhat less realistic, but still challenging battles, then have realistic behaviour (from a RL point of view), that the player can exploit to no end. (This is all assuming that the AI in Attilla, just like in all previous TW games, cannot be modded).