> about losing the property that "all Go code tends to be written in the same general way"

I understand what you're saying but I think (hope?) you're going to be found wrong here. I think that:

(1) very quickly "generic" code will come to be written in a fairly standard way that's accessible to any who cares to spend just a bit of time to know it.

(2) there will be a lot less generic code than concerned Gophers think. I think the generic code will end up in libraries but not so much in application code. Except, of course, in code that uses generic libraries. But using generic code is much more understandable than writing it.

Should be interesting to see how it all shakes out if this latest proposal passes muster. But I think Go will still be much more like "Go" rather than turning into what you dislike about other languages.