In the old discussion, I specifically complained about how it would add back door coroutines to Go via iterators, and now Russ has a post about formalizing the concept of a coroutine, while also keeping the optimization of coroutines as a runtime implementation detail. I feel vindicated. :-)
I've found it's generally a very strong indicator.
But to your point, this isn't a new issue, there's been a good amount of discussion around it over the years.