As someone who's contributed to Eventlet, I've always felt that the only way that it could get over this scary hurdle (and it is legitimately scary) is for it to be integrated within Python itself. Almost all of the weird problems come from fighting with the baked-in assumptions of the Python runtime. Eventlet does try to alleviate the scariness a little bit by allowing you to import "greened" modules rather than changing the global versions, but that has its own problems.
If it were integrated with Python, there would be no monkeypatching, no special magic, it would be just how things work. That said, I'm not at all surprised that Guido doesn't favor a coroutine-based solution; his opposition to general coroutines is as famous as his opposition to anonymous functions. (to clarify: I don't think the @coroutine decorator creates "real" coroutines, any more than generators were already coroutines)
If it were integrated with Python, there would be no monkeypatching, no special magic, it would be just how things work. That said, I'm not at all surprised that Guido doesn't favor a coroutine-based solution; his opposition to general coroutines is as famous as his opposition to anonymous functions. (to clarify: I don't think the @coroutine decorator creates "real" coroutines, any more than generators were already coroutines)