I don't expect anyone to adopt this. Listing complaints about a heavily used standard, and proposing something else incompatible won't gain any traction.
Compare to WTF-8, which solves a different problem (representing invalid 16-bit characters within an 8-bit encoding).
Yeah, WTF-8 is a very straightforward "the spec semi-artificially says we can't do this one thing, and it prevents you from using utf8 under the hood to represent JS and Java strings which allow for unpaired utf16 surrogates, so in practice utf8-except-this-one-thing is the only way to do an in memory representation in things that want to implement or interop round trip with those".
It's literally the exact opposite of this proposal, in that there's an actual concrete problem and how to make it not a problem. This one is a list of weird grievances that aren't actually problems for anyone, like the max code point number.
Compare to WTF-8, which solves a different problem (representing invalid 16-bit characters within an 8-bit encoding).