"Then there's Kyle, who's hypnotically induced blindness seems absolutely harmless in comparison. Rendered him powerless, and was no doubt unpleasant for him, but lacked the level of stress and pain the others involved, even ignoring the potential lethality."
The way this one is carried out was always strange to me. The bad guys sneak into his room and slip the ring on his finger. If they can do that, why not just go one step further and kill him in his sleep.
I can just barely buy that Ra's al Ghul, not wanting to take any chances, doesn't want to risk straying even the slightest from the absolute letter of Batman's plans. But just barely. It would have required only the slightest amount of initiative for them to realize the opportunity before them.