I really wish the whole home theater system was way more modular. I want:
1. A TV that just displays video from an HDMI input.
2. An A/V amplifier that just receives an HDMI A/V signal from a single input, passes the video from that to to the TV, and does Dolby/DTS/whatever decoding of the audio, amplifies the result, and sends it to my speakers.
3. An HDMI switch that I can plug assorted A/V source into (FireTV, Roku, OTA TV tuner, Blu-ray player, Cable box, etc) into, which I'll connect to the A/V receiver.
(Actually, what I really want is for the switch to split the A/V signal into separate audio and video on two different HDMI ports. Video goes to the TV, audio the A/V amplifier--except now it is just an A amplifier. But I think there may be licensing restrictions on that kind of splitting that make it so you can only split at the step that converts to analog for the speakers).
All of the HDMI connections should support Ethernet over HDMI.
None of these should have WiFi built-in. They networking should be via Ethernet. If I want WiFi, I'll add a WiFi access point to the home theater LAN.
I'm not sure how Ethernet over HDMI interacts with HDMI switches. If you have, say, a 4 input, 1 output HDMI switch, does that switch all signals, so that you only have Ethernet between the one selected input and the output, or are the Ethernet lines treated specially and connected like a hub, so that all devices on both sides of the switch can communicated over Ethernet, regardless of which input is currently selected for A/V?
If the later, then the home theater LAN can use the HDMI ports. If the former, then all the devices need an Ethernet port.