I have, from time to time, played the "I can't get behind that" game.
It goes like this:
1) Observe that a lot of older people in my life---and throughout history---are / have been intolerant of something that you find benign (myriad things have taken this role in history: bare ankles, women voting, rock music).
2) Infer by the law of averages that I am probably not very different from most people.
3) Assume I will therefore have a 'thing'that a younger generation will be fine with that I am utterly intolerant of.
4) Try to guess that 'thing.'
It's a hard game. My best guess at this time is "In a world where medical science and services have evolved to the point where life-saving procedures are routine, automated, and five-nines successful, a younger generation will find ever more violent and dangerous versions of (http://en.wikipedia.org/wiki/Choking_game) to be fun to play, and I can't get behind that!"
A bit flipped, but I expect younger generations to be intolerant of the way animals are treated in our society; e.g. mousetraps, factory farming, animal experimentation. I'm not sure how to factor that into your game; "can I get behind future intolerance of behaviours that I consider ordinary" I guess.
I wouldn't think it'd become more common. Personally, I'd say no to the possibility of my qualms going down about it because:
-That is still considered a screwed up thing to do someone,
-It's illegal: you'd be charged(and probably convicted) with attempted murder, or at the very least, assault and battery, which carries significant fines and jail time,
Small wounds often heal within days, yet I don’t go around stabbing people (not even with tiny knives!). Sure, maybe some offences turn from ‘murder’ into ‘grievous bodily harm’, but that shouldn’t be bad in and of itself?
Better recovery would make grievous injury more dangerous for the assailant, not less. Leaving aside murderous intent for a moment, and think about a car accident from reckless driving: the party at fault would be on the hook for the bill, and regrowing complex organs won't be cheap.
If someone's lung or heart can be replaced in a day, do your qualms about stabbing someone in the chest go down?