This document looks mostly good to go. I only have a few questions and some various editorial nits. 

Questions:
- Section 4, last paragraph: Will code points "considered unsafe" be labelled as such, and if so, where? In the derived property IANA tables? (Assuming those tables are kept.)
- Section 5, second paragraph: How will the success of this document's proposed changes be measured in order to determine if further steps towards minimizing confusion are needed?

Nits:
- Section 2, first paragraph, first sentence: It seems a comma is missing after [RFC3491] reference, i.e., "..., commonly known as "IDNA2003" [RFC3490] [RFC3491], ...".
- Section 3, second paragraph: s/full Unicode versions/major Unicode versions?
- Section 3.1: s/also concluded that maintain Unicode/also concluded that Unicode?
- Section 4, third paragraph: Is the requirement that changes which are "documented" redundant with the following "explained" requirement? (That is, perhaps just say "... must be documented and explained."
- Security Considerations, second paragraph: Do "end users" include systems that process or interpret Unicode values? If not, it might help to specifically call them out, as problems may arise from misinterpretation there.