Random late-night, post-practice thoughts:
Mike, hate to say it, but if that black belt said you were grabbing her neck too hard in irimi nage you were almost certainly screwing up the technique, and it has nothing to do with wimpy vs. "realistic" practice. You were just wrong (and it's a common error). Tell her thank you the next time you see her.
Like Mary said, use words. Perfectly fine to say, "Can you give me that attack a little faster? I want to try it at speed." Or, "Go ahead and throw me for real. You don't have to hold back."
Jackie, let us know how that works out for you. I'd say that in the US, after what, 30 years of Title 9, the difference in gender expectations are way less than you think. The distinction is less gender than what people want out of their practice. I'm still thinking of the lovely young lady who I will swear picked me up to shoulder height in a tenchi nage before burying me in the mat. Would you deprive me of an experience like that?
I sure will. I am betting there will be less issues, people will be more comfortable when the sexes have their own class. When the sexes do come together it is more advantageous experience for women. It feels good, in the terms you laid out, to throw a 220 lbs 6'3 guy. How much benefit does the guy get from that experience? It isn't going to as much as the female. That has me thinking in part for the idea the occasional meeting of the sexes for practice. I am looking at possibly once a month class for those who want to do it. Women feel less intimated and a whole lots of other things when men are around. There are lots of women only actives for women. Men have their groups too. I don't see both sexes running in open arms to each other. Because of my observation I don't want go against that pushing together men and women. Am figuring why force a situation upon people that they are uncomfortable with that situation. They aren't going to stay, they won't tell their friends about it if the dojo is an uncomfortable place to be for them. I want to provide them an environment they are comfortable in. That is my idea, it seems naive am sure. It's going to be a learning curve of hard knocks. I have to keep a finger of the pulse of society. I hope it works.