I prefer to think of the current AI as a placeholder for when the real AI is implemented.
AI from scratch
1: check health/morale and set status
(different thresholds for different species, % of health/morale combo?)
cower, flee, insane, berserk, normal
examples:
bloodspider [flee 0-15, berserk 16-40, normal 41+]
taman [cower 0-5, insane 6-10, flee 11-25, berserk 26-55, normal 56+]
ortnok [flee 0-7, insane 8-16, berserk 17-45, normal 46+]
2: implement status per alien
examples:
normal= get weapon, move to comfort zone, do job
flee= maximum movement away from enemy and out of LoS
berserk= get weapon, move closer and/or attack nearest enemy in LoS with preferred attacks
comfort zone: a set of parameters per alien species defining things like minimum and maximum distances to allies and enemies, attack preferences (most attacks, highest damage, highest hit %), target preferences (civies, objects, players, nearest enemy, best % to hit enemy, enemy nearest death), concealment and movement preferences.
The distance to allies and enemies is to be a simple way to diversify AI tactics. Giving bloodspiders low minimums and maximums will make them clump up and rush the player, if hovernets have high numbers they will spread out and stay at distance. A high minimum and low maximum will make them stay at range from each other but move as a group, while no minimum and a max higher than the map size will let them wander at will. Combine with movement and concealment preferences to generate more dynamic action, hovernets and shevvar use 25% TUs moving, taman and ortnoks always reserve TU for RF, taman and bloodspiders always move out of LoS if they see more than 2 enemies.
The distance thing also allows for a check to the nearest ally/enemy, develop a path to it, path as far along that path as possible. This would be a troubling "perfect enemy information" thing normally but the telepathy virus/parasite allows it to work for the aliens knowing where they are in relation to each other. If need be we can use that for them finding the player or mock up a ranged brain wave scanner of some sort (improved IR goggle type thing or psi-detector that finds humans?) that allows this.
Pros: Different aliens show different tactics, solves harvester pathing issue
Cons: Needs flowcharting and programming that I'm not up to