1. It's an Amazon issue, not Roku. Yes, they seem to have fixed the issue in the US (just last week), so hopefully they'll apply the fix to other regions.
2. Netflix issue. Seen others post the same thing. You might try disabling auto-framerate if you have that on.
3. Netflix issue, and they don't seem to care that so many people hate it. Nope, can't turn it off.
4. The forum is mostly users helping users. Yes, Roku monitors the forum and occasionally offers help. But the developers themselves rarely appear here.
I read forums on the Shield, and they have their own set of issues, some even mirroring issues with Roku. I don't follow any ATV forums, but I've heard of problems there as well. There is no perfect streaming player.
Dan
Roku Stick (3600), Ultra (4640), Premiere (3920), Insignia 720p Roku TV, Sharp 4K Roku TV, Nvidia Shield, Windows 10 Pro x64 running Serviio and Plex on a wired Gigabit network.