I've only tried to use auto resolve a couple of times (other than naval.) Each time it gave really screwy results. It was on very hard/very hard. It tended to produce casualties in my best units or kill off family members. Being that all of the battles I would autoresolve are very easy wins even on very hard, I have been unwilling to accept the completely random results. Outnumbering 10:1 didn't give good results. Perhaps it is better if you play as Romans. As Carthage, it stinks.

I have not auto resolved since the "elephant fiasco." I had a nice stack for conquering the small settlements in Numidia. It had one elephant unit for the gates. So I start running into the typical, single unit along the road during hte long march. Usually, I attack, they withdraw, then I attack the 2nd time, and send my cav off to kill it in a pincer losing maybe 4 or 5 men. That clears the road and my army advances until it hits another obstacle or runs out of movement points.

So here I am facing a lone archer unit on the open desert. I had done this a few times before. Race out with cav, run the unit down, its over. Unit is gone from the map. What happens with autoresolve? 60% of the enemy unit survives, and it is able to withdraw...meaning I will have to do this all over again. My elephants lose 10 or 11 out of 12 making them worthless, and I take as many total casualties as the archers. I'll get to face it again on another turn, yay!

While this example sticks out, my other auto resolve experiences were similarly awful. Maybe the AI screws the player in auto resolve when they play as Carthage? I have noticed the naval auto resolve has been surprisingly favorable now that I'm playing as the Brutii on very hard/very hard. It is completely different.