I know exactly what you mean. Look up my post "Some examples on why the AI on intelligent needs to be better"
It's longer but details some of the obvious problems I've seen with the AI.
The AI never seems to plan "how do I defend" or "how do I attack" like a human would. People recon to determine enemy strength, and then plan an attack/defense based on likely odds of winning. If the odds don't look good, a human would look to other ways to get better odds or cancel the attack/retreat. Other ways to get better odds include delaying the attack to build up fleet strength, or taking out that starbase that's pumping up the enemy ship stats.
The AI doesn't seem to take into account odds of winning at all, it seems to just hit me with it's current best fleet, even if I just wiped out 3 or 4 of its current best fleets with minimal losses.
The AI also doesn't appear to take into account probability of being attacked by a superior fleet during the next turn. The AI often sends single ships/smaller fleets into range of my larger fleets, it's like like throwing them away.
