Personally im quite pissed off. I already restarted the campaign 2 times already with different difficultysettings and in both cases the Ai didnt put up a fight even for a single battle. The only time I got even briefly scared was when my platoons where even more then halfed due to the plauge. But even then there was no pressure, cause the enemies armies casualtyrate due to plague was also high. And my platoon consisted out of very high level spartan infantry units, while they had a few militaunits. So im gonna have to restart the 3rd time.
Im really not the kind of player that likes loosing and heavy difficultylevel, like general X-complayers. I always like to win in SP, but in this case, its too ridiculous even for my taste.
Maybe im just the lucky guy but since release every battles I fought the AI used all its units at peak efficiency (minus those times where they tried to capture the flag running through my army, or when they fail at besieging).
Then what I agree with you is that an army with high tradition and high experience units, when preserved (then further enhanced) is able to roll on most AI armies that are of the same size : I very rarely encountered a AI army that had more than bronze chevron or a 3 star general. They die too much (both generals and units) to be able to muster epic ones.
To circumvent this problem I have to force myself to send my epic generals/armies into dangerous situations. When you have to replace you lost units with recruits, and a 6 star general with a 1 star one, it changes all.
When my overly experienced general dies, I'm sad about the lost traits and all, but I'm actually encouraged to continue the legacy of the army he led with a newly appointed general, because I know the battles ahead will be 100x tougher.
