Mind War is way too powerful at the moment. There is basically no way to counter it. I just ran into it for the first time, and it is incredibly frustrating, even if it doesn't really have a massive effect. So far I have had a soldier mind controlled every single turn, and it is frustrating because I cannot do anything. Having a trooper drop their weapon or whatever is dumb and not interesting, because it just delays me. This isn't helped by the only two psyons visible that I haven't killed running away for no apparent reason. I wouldn't be frustrated if I could see whatever psyon is mind controlling my guys and kill it, but I can't.
In short, Mind War needs to be limited to line of sight, as otherwise it is just delaying me and being frustrating without adding to gameplay at all.