Total agreement...
I think the 16 -channel "Super Processor" is a very interesting product category with a lot of potential if the manufacturers ever get it figured out properly for general home usage. Not everybody needs, wants, or can even use that many channels, but a 7.4.6 isn't completely uncommon in many build-outs I've seen. Do the math, though, and it becomes apparent that many HT Hobbyists with a dedicated room are easily tapping out the potential.
Those that support Dirac Live and the Bass Control Module require independent channels for the Subs, so no mDSP 2x4. Expanding that channel count upwards to the Luxury brands like Storm, Trinnov, etc is prohibitive for many. That's why products like the HTP-1 and the RMC-1 could be so valuable, especially the RMC-1 with that expansion module. (Too bad it doesn't work, and that module doesn't exist!
Frankly, I think Anthem's AVM-90 is an almost perfect implementation of 15-channels +4 Sub outputs (assuming these Sub Outputs are truly independent). (And assuming Anthem gets their gear to just flippin' work!)
Unfortunately, the economy of scale just isn't on the consumers side. There are plenty that seem to want them, but that "plenty" is a drop in the bucket of actual households that may support a more normal HT AVR or Processor.