I haven't played with SEIV's or SEV's AI scripting. Are there triggers? I've played with other games' AI scripts, and it seems like reacting to events is always a huge missing element differentiating AIs from humans.
For example:
In SE, if a human suddenly encounters a race with good missiles or fighters, he will either
a) make PD a research priority, or
b) desperately trade for PD, or
c) go into defensive mode, or
d) assiduously avoid that race, or
e) make extra-nice with that race, or
f) go all-out to destroy that race quickly.
Another example:
If a human is losing colony after colony to one player and the situation is hopeless, he will either
a) quit
, or
b) surrender, or
c) try to negotiate a protectorate deal, or
d) get vindictive by going kamikaze, or
e) get vindictive by surrendering to another player.
But the AIs just seem to go on with whatever strategy that was pre-mapped out for them, regardless of the circumstances. Triggered behaviors would solve a lot of that problem, and they could be tuned for each race to match that race's personality.