I figured I would jump into the fray here with my two-sense on the issue.
I too, stumbled upon this problem with interference and discovered a "rogue AP" always stomping on my WiFi signal and figured out that device was the Roku. As I understand it, these devices only have a single WiFi radio. Therefore, the Roku can only connect to one channel at a time, meaning that whatever channel your WiFi is on will be the same one the Roku uses for WiFi-Direct. Without two radios, this is unavoidable.
The Roku uses the WiFi direct signal for, among other things, the fancy voice remotes and also seems to use it for the Roku app remote on smartphones as well as for remote streaming audio if you want to use headphones attached to your phone to avoid disturbing your housemates. These are actually all good features and also means that the WiFi remotes do not require line of sight like the old IR remotes do.
Bluetooth and ZigBee, etc aren't really a fix because they also use the same public frequencies the WiFi does. You probably don't notice interruptions in areas with light to moderate traffic on 2.4Ghz because most Access Points have Bluetooth Interference Mitigation turned on by default which actually tells the AP to temporarily stop broadcasting so the Bluetooth signal can be broadcast. I think the saving grace is that Bluetooth transmissions tend be short and the protocol also uses frequency hopping that will still interfere with WiFi BUT the built in error correction in the WiFi signal masks this interference.
I also find the pearl clutching and hand wringing in the thread to be a bit over-the-top, especially with the threats and whatnot, considering that the use of this public spectrum is completely unregulated and is basically used cooperatively by "gentleman's agreement" if you will. If you really want to see some action go find an old first gen Cobra 2.4Ghz frequency hopping cordless phone from the late 90s or an old school 2.4Ghz wireless camera and it will probably completely obliterate every signal on the block when being used, and there is absolutely nothing you can do about it, except buy your neighbor a new one that doesn't do that.
The main problem with the WiFi-Direct implementation seems to be the extremely strong broadcast power of the signal. I think Roku could probably go a long way to mitigating the problem if they provided some menu option to control the power level of the WiFi-Direct AP the device broadcasts or even the ability to turn it off. From my terse understanding of WiFi-Direct, I believe it's also keying the RTS/CTS flag on the channel which basically causes every device to stop broadcasting when he WiFi-Direct device requests air time. Obviously, this will slow things down.
I feel the thread's pain on this. I live in a region of the country with weather patterns that make for extremely favorable signal propagation conditions. I live in a single family home on a typical tract and can see approximately 80 wireless networks from the bottom floor of the house and even more if I go up to the second floor. Indeed, there are numerous Roku devices in the area and they all seem to love to camp out on either channel 36 or 165. The combined effect of all of the "screaming" Wifi-Direct APs on channel 36 has now made channel 36 almost completely unusable in the entire neighborhood. Worse yet, I'm a few miles away from a major airport and a doppler radar installation and a military base so all of the DFS channels cannot be used here. This means that basically everyone on the neighborhood with a 5Ghz router is fighting for airtime on channels 149-161 or for the layman, there is basically ONE usable 5Ghz channel for the entire development of 80 houses.
In terms of what can be done about it... disabling Direct Connection on the Roku seems to turn off the AP, at least on the 2 devices that I own. This also means that the fancy remote and app features won't work and you have to use an IR remote. A high quality router with a good strong signal helps. I'm talking $200+ territory, not the cheapie Belkin from Best Buy. In a commercial environment, these types of issues are resolved by placing 1 or more access points at LOW power in EVERY room, typically managed by a controller of some kind. Ubiquity makes a setup that you can get your hands on for less than $500. You can also install higher gain antennas on the router or install more directional antennas on the router you already own. They also make paint that will turn your rooms into a Faraday cage blocking all the outside signals, including your cell phone.
I get that WiFi direct does give some nice features - streaming audio, etc. But they are nice-to-have's that are infrequently used by most people compared to the core functionality of reliable high quality streaming. At the end of the day, the stability of the wifi in your house and quality of streaming over mobile devices that need reliable WiFi is THE most important thing.
Since investing in Roku, i've plowed >$300 into APs for each floor, $150 on MoCA adapters, and invested in running additional ethernet cables to literally everything that I could to reduce overall home reliance on WiFi. That alone has its benefits (wifi is quite terrible compared to hardwiring). Thankfully the faraday fabric only set me back about $20 and prevents interference returning from the random 're-enabling' of WiFi direct when auto updates or auto-reboots happen.
I agree with you that the simplest and easiest thing to do, and probably already supported in their firmware is to configure the wifi radio on/off and expose a power level setting like most routers do. It would cost Roku very little to support this for their devices that do have firmware level support. (we know they do for wifi radios on/off since thats the point of this feature request).
Right. I was just trying to put my experience out there along with some suggestions for others who read the thread, in hopes that maybe someone at Roku will read this and decide to open a feature request and schedule it on the roadmap.
In terms of home managed WiFi, as a previous IT professional who worked in the industry for 17 years, and an "enthusiast" since about 9 years old, I think a move away from single "one device does it all" routers at the consumer level is somewhat inevitable. This model has been marketed in a day when WiFi devices were kind of a "luxury accessory" for consumers rather than an every day need.
I just checked and I have 18 devices connected to my home WiFi at this moment. Despite being a former IT professional, in terms of home wireless tech, I don't even consider myself a "power user." My previous next door neighbors had a completely Alexa voice controlled setup running in their house. Everything from Microwave to Toaster to Dishwasher to Washing Machine, and all the lighting and sound. They had well over 50 devices on their network, and were pretty consistently having WiFi problems with their single AP. Sadly, in the future I think this is going to become the norm more than the exception.
If its not being done already, I expect that new home builds in the near future are quite likely to come with a central WiFi system pre-installed, just like all the other fixtures in the house. In return, I expect "old school creature comforts" like light switches(and the wiring for them) are probably going to go away. The WiFi connected voice recognition and sensor system will be handling all of that along with the WiFi lights.
In my personal opinion standard wifi is not the answer for smart home iot. There are too many devices and device types, and when you add bandwidth congestion it's basically a nightmare for devices you need a near realtime response. What's really needed is a more specialized protocol between a home automation hub and each device, where the most critical devices are hardwired. Even a custom protocol on standard wifi frequency range would be better than letting a router, which is designed for 'airtime fairness' and will stop all traffic for poor wifi clients under certain circumstances.
Before becoming aware of any of my troubles with Roku, I did a simple test - hit the volume button 10 times in a row on a wifi remote. You will see that you don't usually get back all 10 responses, and you will see significant delays between keypress and result.
As an example, at some point 2 years ago Logitech removed support for IR for Roku devices that had WiFi Direct, forcing me to use WiFi for my Logitech remotes. It was terrible as expected from this post, as the Roku's own WiFi direct interferes with it's connection to the router (if not hard wired).
When I chatted with support from Logitech they re-enabled the support for IR to my Harmony profile. He said they get that complaint a lot so they re-enabled IR support for Roku for people like me that have terrible quality of remote commands in Roku devices with WiFi direct. If that's not telling, then what is!