I've noticed this as well - most recently in a 5 on 5 domination match - I was the lone human on my team with four comp assistants, playing against three humans and two comps (terrible odds to begin with).

The comps moved around and attempted to capture objectives/kill opposing demigods until about halfway through the match, then it's like their AI just shut down.  Kinda sucks that I was the only one actually moving - the AI either stayed at the item vendor or stood near a captured flag. They ended up at level 9 when I was 20.

A human player started attacking one of the ones standing near a flag, and my teammate didn't move.  One heck of an easy kill for the other team, then he spawned at the item vendor and didn't move the rest of the game, just like the rest.

I do believe you should expect the AI to move, though...

I'd expect them to at least auto attack though. That's the least they could do.

My experience with the singleplayer stuff is that on normal the tournament is a complete walkover. 

But on Hard I have yet to win my first game.. from what I see happening mostly because the teammates AI are completely getting their asses kicked. I'm playing the Rook btw. I find the enemy AI doing a decent job, retreating when almost dead and chasing me when I'm almost dead. Its pretty tough to kill another demigod with the rook as its always slower. 

But playing four of them with hardly useful teammates its a nice challenge in the end.  

I wonder how you guys experience this?

I will only play with any form of ai if i absolutely positively have no other option - which is like, hardly ever. I've never actually ever seen an RTS where the ai behaved even partially like a human. Some way some how it's always just plain retarded. Most recent case of this is dawn of war 2. You play a 3v3 and have a teammate drop then you were stuck with a retarded ai that would just suicide attack the enemy base while pinging the map non-stop. While this has been improved somewhat, it's still effectively cancerous. On the other hand, while they suck balls in one area, on the other hand it's also super anal about capturing points and upgrading them. So it's 50/50.

From the manual:

* Easy AI. At “easy” the computer players receive fewer hit points and less gold than the human player.
* Normal AI. At Normal, the computer players have the same hit points but get slightly less gold from gold mines than human players.
* Hard AI. At hard, the computer players receive the same gold and same HP as their human opponents.
* Nightmare AI. At nightmare level, the computer players get a lot more gold and slightly more HP than humans do.

So Hard is the same as human. If you cant beat a Hard AI then I would say the AI is pretty good

hmmm a bit unrelated but concerning the rook, if you get items boosting his speed he can be nightmarish.

just takes a bit of tinkering to get him there

I have just checked the code and the manual lied. The actual settings are:

[code] 

 # Difficuly handicaps for the three different AI difficulty levels
    DifficultyHandicaps = {
        # Easy
        {
            GoldMultiplier = 0.75,
            ExpMultiplier = 0.75,
            StartingGold = 0.5,
            MinPoints = 0,      # MinPoints and MaxPoints is the range of points the AI is allowed to spend on an achievement item
            MaxPoints = 150,
        },

        # Normal
        {
            MinPoints = 150,
            MaxPoints = 300,
        },

        # Hard
        {
            GoldMultiplier = 1.5,
            ExpMultiplier = 1.5,
            StartingGold = 2.0,
            MinPoints = 300,
            MaxPoints = 450,
        },

        # Nightmare
        {
            GoldMultiplier = 2.0,
            ExpMultiplier = 2.0,
            StartingGold = 4.0,
            MinPoints = 450,
            MaxPoints = 10000,
        },
    },

[/code]

So normal is really the same as the player.