Enemies shouldn't automatically know your defense values; instead, they should have 2 stats:
Probe Chance: Chance of targeting someone based on their stats, or not at all if nobody has stats that would be targeted for mind control under current system;
Confidence: Chance that if Probe Chance doesn't trigger, they Mind Control a random target.
This does a few things.
1:Ameliorates the issue of 'lightning rod' troops being set up to always get mind controlled to no actual effect.
2:Allows players who build squads of well defended troops to feel satisfaction when enemies try to mind control them to no effect.
There could be a 3rd variable for apparent vulnerability to weight random targeting so Hybrid agents or agents in armor with anti-psi effects don't get targeted as often.