The collision which led to the red card was between a fullback and a number seven (open side flanker). The first Welsh open side I can remember is John Taylor who I’d guess was an inch or two short of six foot and I doubt it if he weighed thirteen stone - I’d guess Curry weighs five stone more than Taylor did in his playing days. Is it an exaggeration to say your average international rugby player weighs about a third more than they did when it was an amateur sport? I don’t think it is, in fact it could be an under estimation.
American Footballers first started wearing protective clothing in the 1890s and I see no difference in the severity of collisions in the two sports now. I think the time has come to either start wearing some form of protective clothing or for drastic changes to the tackle laws as you suggest.
As for the game, it’s turning out that the sending off was the best thing that could have happened to England.