In addition, I believe the trust documents identifying the trustor are filed with the FAA, so this information is not opaque at the regulatory level
That is correct; the FAA doesn't like trusts which hide the identity of the beneficial owner (the trustor). This was stated at the lawyer's meeting I went to.
GEP's writeup of the FAA position is also consistent with their position back then. They don't like anonymous trusts, and they don't like trusts where the trustor can boot out the trustee easily (e.g. a pre-signed Bill of Sale).
Nothing new here, at all.