I agree that self-defense is a perfectly legitimate use.
Using it on prisoners for ease of transport is crossing the line IMO. You're using it for your own convenience, not out of necessity. I mean, you could also make the prisoners easier to transport by slitting their throats; but I think most people would agree that's venturing into evil territory.
Generally, I think that's a pretty good metric for use of dominate. If it would be acceptable to kill someone in a given situation, it's okay to dominate that person instead. If not, probably not.
I totally disagree with this you are in the wilderness and you have prisoners you have several choices you can kill them which is the easiest thing to do. You can tie them up and take every precaution that they won't get out of their bonds and kill you while you sleep or worse alert their comrades.of your position. Or you can dominate them with the order not to escape or make noise.
I think if more players looked at and used dominate that way they would be less likely to kill prisoners.
I was in a situation where we had to sneak through enemy territory to stop a gate from opening to the infernal plane. We got into a fight that left one of the enemy soldiers alive. He himself was not evil he was just a loyal soldier working for his Kind who he didn't know was evil.
We tried to convince him but he did not believe us. We couldn't drag him with us and chance him giving us away or leave him tied up and take the chance he would escape and alert them we were coming. Our mission depending entirely on sneaking in. So we slit his throat. Dominating him would have been a much kinder fate.
Also say you are transporting a very evil and powerful bad guy through a city full of innocent people for his trial. What would be better a dominate on him preventing him from trying to escape or just hoping that your bonds and guards are enough. And if he does escape killing innocent people how do justify well we could have stopped him from doing this but we didn't want to take his free will away from him.
I don't see using dominate for things like this as evil. It just make sense that if you have this magical ability you would use it to protect the people and for the greater good.