I don't know if there's any one place to read up on this info, but a few observations:

• The primary determiner of a target is usually "can i kill it". This tends to supercede all other calculations, unless there's a specific exception (EG hydra head targeting mechanics). However, the "can i kill it" is not done the way that a human being would do it. I don't know exactly how the math is done internally, but my guess is it errs significantly on the side of caution - so even though you might think it's obviously an easy kill, the AI may not.
• After the above, the next determiner is generally affinity. AI tends to prioritize weak-affinity targets.
• When possible, the AI usually tries to debuff, and it usually prioritizes CC debuffs. This means if your A1 has a debuff, despite the fact that it is weaker, the AI will still try to use it. The most obvious case of this would be a champ like Rae, who has an AOE DEF down on her A1. She'll use that instead of her A2, which would do more damage - but she'll use the A3 over the A1, since the A3 freezes.
• When none of the above are a factor, the target is usually the team lead.

My answer would be: "HORRIBLY!!!!

It used to be the thing that bothered me most about the game, but now I hope it stays as is :)

2 reasons:

1. We have presets to control, albeit limited, how our teams function on auto.

2. We can play manually and be smart, against a pvp or pve opponent stuck with arbiter wasting a revive in round 2...

I wish we could have specific controls for dungeons, namely, in each wave, who to target first and other such things. For example, in DL, my champs always leave the unkillable guy for last. And this dude has speed of like 22 LOL. So i have to watch all my toons go round and round and round and wait for his TM to fill up and get his turn, so i can kill the bugger. Ya i know, i can bring a debuffer, but what's the point, the Dragon doesnt put buffs, so you can bring champs to kill waves faster, then dragon killing is slow, or the opposite. Very annoying.

There is AI? i never noticed.

ofc there is not lol. but its not a simple script either. in some similar games, ive played, champs really do use their abilities in a simple order. and its really worse than what we have here.

I was only half joking - i sometimes watch the fights on auto and it seems at times as if the AI is picking the worst possible choice

One enemy left, almost dead? - expect mithrala to use her shield and strengthen buff instead of finishing the job (many buffing champs do this)

Enemy got no buffs?. Doesnt matter to Yasmin she will still open by trying to remove buffs

Hydra head got your champ? expect the ai to ignore it, and also on hydra expect them to focus on the head with an active shield up

Many more examples but wont bore people further.

I know they do not quite cycle through their skills by rote but it feels like it

Having said all that, bad AI helps me in arena, especially with revivers, and at least we can program by wave now so its not all bad.