Hi Gene,
Yes that was my take from it. No to the Atmos, Dts:X, Auro 3d conversions unless via PCM. Yes to the Dolby True HD, Dts HDMA and below/older. With PCM unaffected regardless of Stereo or multi channel.
If this take on it, including Denon's, is correct then it is pretty much as it is now. Since all manufacturers support the Atmos and Dts:X and some additionally support Auro 3d I don't see a concern over not allowing conversion between these. Denon's solution to the overhead layout seems good with having 15 assignable outputs over 13 actual outputs and configuring on the fly which format uses which speaker layout for amps or pre-outs.
We can but hope