I think you may find, back when ADTG first posted the specs for the 5200, I suggested it was a compliance move to cover the 5100 from the required Dolby changes. It was to apply to all current models, although given Denon and Marantz reluctance, it may just now apply to new ones as of this year. I do not see any indications the Denon 8500H or Marantz 8805 getting the update, my 6012 has had two updates this year and nothing has changed in that regard. Who knows perhaps Dolby will drop this entirely.
IMO the 5200 was a disappointment with only minor tweaks and therefore not worth an upgrade for me. It is still a fine processor, minus obviously Gene's recent findings.
Since Yamaha does like to do Hdmi right, with the certification, then most likely they will wait with the 2.1/8K chips impending. Additionally there will be a few more 8K offering from Tv/Projector manufacturers. Hopefully they will do 13 or 15 and give us 9.2.6 options.
I could be wrong but I don't think Yamaha has done wides previously, I certainly can't remember any models with it, but it would be nice.
Auro 3D aside, I don't believe there is any new codecs beyond the Dolby equivalent of Virtual Nerual X and the 5200 could probably be upgraded with it (honestly there is no real reason the 5100 could not get it either). Dts:X Pro however may need to wait for the next model and it would be a good reason to up the channel count, it would not likely alter/improve the existing models.
Last thing
, question for Gene, since we don't have a dedicate thread as yet. The issue you noticed in the MX5200 regarding the channel power drop, very nice video and well worth the watch for me.
This was only when one channel was linked and the other one wasn't. You got two readings, one where it stayed at the expected power and one where it dropped to half. Was that only one or both channels of the unlinked pair the drop occurs? Were the other remaining 7 unaffected since they cannot be linked?