How about we treat pain like we regard salt.
Can't exist without it, while too much can maim or kill.
Enlightened minds, with well trained bodies, may find the right amount of well earned compassion, to use just enough to make training that much more palatable, meaningful and satisfying.
A nice analogy actually, but for me, I would have to say that there are some foods that I do not use salt with at all - in this case, my Aikido. Different palettes, different people, different restaurants.
There can be a "place for pain" in Aikido training in terms of helping people understand that in any "self-defense situation" one may very well get hit, bruised etc. in any encounter. If that experience impacts them enough such that they cannot stay present, then it can be a good idea to work with that process at a certain level so the person can get accoustomed to the experience so they can deal with it in real life. But that is a completely different aspect than what this thread is about, as far as I understand it. I'm talking about the application of Aikido waza.