SMAC: Should I use Psi attack?
I am late game Alien Crossfire, attacking with gravitons aremed with string disruptor.
Unfortunately, the others have gotten wise and are building everything AAA. In a way, that's good, as it is expensive, and diverts their resources.
However, I can no longer "one hit kill", and am losing gravitons.
Should I replace the weapons with Psi attack?
Solution 1:
Psi attack/defense is orthogonal to conventional weapons. Its result depends on Morale levels of attacking/defending units.
If an attacker/defender is a Mind Worm, they have their own class, plus both faction's Planet (Green) scores/attitudes largely affect the outcome of the fight.
Answer: see what's your faction's Morale and/or Green score.
You may also trick the system by changing your Government/Economy type before the attack. Say, if you possess some Mind Worms and you are planning to give them a victorious ride, switch to Green several turns before the planned invasion. Or to Fundamentalist + Power if you are planning Psi attacks with conventional units.
Personally, I love Green because if you are lucky enough, you can capture native life forms, making a considerable amount of your units Mind Worms (Independent) which means it requires no support from a home base, still performing as police in "at least one unit defending each Base" paradigm.
Solution 2:
If you have dominant weapons, mixing in hovertanks and even air-dropped infantry will let you continue leveraging those dominant weapons.
Psi-combat is mostly useful when facing technologically superior enemies that your weapons cannot defeat. Switching from overwhelming firepower to psi-attack will make you lose as many (if not more) units, since psi-combat is less lopsided in general.
I'd say consider changing your gravs to transports and using their mobility to deploy slower, ground-based units that ignore AAA. At least until your opponents stop putting all of their eggs in one basket.