this is a re-post of something that crept up on me while writing in another thread:
I was thinking about the mechanics of PSI-attacks and mind-controlling.
if you want to make somebody do something, you have to act out all his actions in your mind and project them into his brain. simple commands like "run forward" would probably take next to no time.
but reacting on the environment? you'd have to be in the victim's mind in real-time, so you would need at least as much time for mind-controlling him as he would need for doing that stuff himself.
even if the mind-control is acting on a more abstract level (giving impulses like "run forward", "shoot at that moving unit", "activate and drop a grenade"), it should still cost time-units
based on the victims actions.
this could be used to balance PSI more, because the old "PSI soldier with 100 TUs can make four aliens run amok across the entire playing field" would no longer work - the PSI soldier's TUs would only be enough for either making one unit do a lot of stuff, or for making several units do very basic stuff like killing themselves.
when a PSI soldier is controlling an alien, everything he makes the alien do would
also use some of the soldier's time units. the exact amount (half of the time units are also subtracted from the controlling soldier?) would have to be determined by play-testing, to make sure it feels right. the amount (or rather the fraction) of TUs used could also depend on the PSI skill level. that way, ethereals could still be very deadly