What is your evaluation of the proposal?
Is the problem being addressed significant enough to warrant a change to Swift?
Does this proposal fit well with the feel and direction of Swift?
Yes! It lowers the barrier for Standard Library Contributors in an ABI-Stable world, and will also lead to better real-world tested code landing into the Standard Library.
If you have used other languages or libraries with a similar feature, how do you feel that this proposal compares to those?
How much effort did you put into your review? A glance, a quick reading, or an in-depth study?
About the 1-year period for feature removal: Since the goal for this package is to be used in real-production code, I think the 1 year time period for features removal is fine; if we really want to push it down it could probably be a six months period.
Something that I haven’t seen but I think is very important for this package to achieve its goal: how is this package going to be exposed to the community?
We need to push the SwiftPreview package so it can be used not only by the folks who participates in the forums.
I think this package deserves a spot or at least a mention in swift.org, it can be mentioned under the Standard Library Design section, or if it becomes important enough in the Swift community, it can be under the Projects section in the sidebar.
Also, the release of this package deserves a blog post in the Swift blog.