Super late reply, I don't have anything against AVRs per se except maybe footprint (they tend to be huge and I like lower profile gear), and I'm also more of a two channel / audio guy at heart. and never saw myself getting much past 5.1 And AVR's have a whole lot of features I'm not likely to use. The one feature that many do have that is great is DSP, but I already have a minidsp that I use for sub integration so I've got some of the room correction handled.
So, meantime, in the intervening time between posts, I did buy the used Oppo, 103 have added a center channel speaker and also added a Parasound P7 preamp in place of the Schiit Freya - the Parasound preamp was a near necessity for integration as I wanted to run three Schiit Aegirs in balanced/bridged mode across the front three channels with my KEF LS50 Metas and the Parasound has balanced Ins/Outs for up to 7 channels. I confess that adding the center channel was kind of a revelation - much more realistic audio now.
I have also purchase a Essence Evolve II-4K HDMI v2.0 Multi-Channel (5.1) DAC that Kal Rubinson had recommended. Haven't tried that yet, it's sort of an insurance policy in case the Oppo has issues, but I imagine curiosity will get the best of me and I'll stick it in the system at some stage.