Regarding Note to Balloters:

Not #1 or 2.
This profile seems to be designed to support the "assessment and plan" text "typically contained within a clinical note" - i.e., an episode-specific assertion that may be overridden at future episodes but is not to be managed as a longitudinal asset. The CarePlan resource is designed for longitudinal management. We do not wish to prohibit CarePlan from this "episodic" use, and it may even be a useful first-step for some implementers, but it should not be the only permissible use, or the only use encouraged by specification.  

Not #3.
Implementers tend to ignore things not in US Core, so it would be bad for the profile to be retired. 

I favor #4, with caveats:
The category slice should be removed. If the whole thing is "assess-plan" then it goes in a Note.
If Assessment & Plan Notes are to be provided via DocumentReference, then that supports the USCDI requirement.
How such a Note should be associated with a CarePlan would depend on the use case.
Requiring a narrative summary is a good thing. Reiterate the proper use of 'additional' narrative.