Personally, I'm OK with the wording in the 3.5.0b2 docs, as far as basic terminology and glossary-style information goes.

I think coroutines, async, and event loops are badly under-documented in the broader context, though - there is very little in the docs explaining the concepts and constraints[1] of Python's async features. Unfortunately, the people with the knowledge of the subject are likely to be too close to the details to be able to write beginner-level documentation, and beginners don't know enough (by definition) to do so. I'm trying to do some playing round with creating my own async framework to get a better understanding of how things should work, but it's slow going and honestly I don't feel I've got anything much I could write up at this point.

[1] For example, how Python's implementation differs from other languages or "theoretical" discussions of coroutines in the literature.