3. gen exception passing --> deferred, needs case building
OK (or you could give up now while you're ahead :-).
4. gen parameter passing --> deferred, needs alternatives explored
That one was already taken out of the PEP. I think that #3 probably fits better in the new PEP you were gonna write for #4. But to be honest, I don't encourage you to write it -- I expect I'm gonna reject both in the end. But I can't stop you. :-)
That's cool. Better to be fully thought out, documented, and rejected than to be half-baked and in limbo for perpetuity. Besides, you might even like the revised proposal. I think I've found a very clean, consistent, pythonic way to avoid the problem with the thrown away call to next(). rejection-is-a-form-of-progress-ly yours, Raymond Hettinger