What you say about newbies and their fear of heeling is true. That's what my experience with my 22-year-old son was. He is not interested in joining me when I take my Hunter 170 out, which sucks.
Here's the thing; the sailing experience is not just about boat performance. Part of the equation for me is the social aspect, and the comfort of my passengers is important in that regard. Friends, kids, grand kids, etc. will be those I am hoping will be enthusiastic about joining me and my wife for a sail. If the first time they go for a sail they get spooked, it is not likely I will be able to persuade them to come out a second time
I don't intend to let my passengers "dictate" to me, but if I don't make some accommodation for their enjoyment and comfort, they will stay on shore.
This is why the more I think about it, the more I am inclined to own 2 boats - one for comfort and one for sport.
Completely agree with you regarding the social aspect. That is what it's about for me also. When the wife or neighbors look uncomfortable, I get them to move toward the rail and I let out the sheets, or pick a new point of sail. My younger daughter and her friends would tolerate sailing at 5 knots for an hour or two. After that, they wanted to go on a planing run up the river at full throttle - the reason I own a bipolar boat...
While some heel is inevitable, you can certainly control it so that it stays reasonable. If 10 degrees is too much for your crowd, you may have to go multi hull, though.
It is possible that a bigger boat might make your son a more willing participant. The 170 is full contact sailing - not a leisurely, shady, day on the water... Whatever the reason, it's a shame he doesn't enjoy sailing with you. I feel your pain. My daughters will all go, but they don't go often since they live out of town.
It may have come across more harsh than I meant it, but I wouldn't consider how newbies react when selecting my boat. However, I would definitely consider them when we were on the boat sailing... Happy Boat Hunting.