While I there are so many small issues and missing features in all my Apple products that I'd love to see to fixed or added, tvOS is the one I most wish would see a significant redesign. For years, I've never understood the approach of having the Apple TV screen (which is a good start) and the App screen. Also made far more sense to be on one page, where picking up where you left off is the most important but then also easily finding recommended shows based on what you've watched and liked. As well as offering much better family and kid support. Google TV redesigned this year, and did essentially all of that but runs on relatively slow hardware.
I would absolutely love to see a similar redesign with content focus rather than app focus, but I feel strongly it won't happen anytime soon and rather we will see minor pushes in that direction over many years. If they continue to take too long, and more flock to Google TV which is far cheaper, Apple may come too late, especially if Google ever gets serious about Google TV hardware for users willing to pay a premium and if they get Netflix to integrate fully again.
While the Apple remote is of course far better than the last version, it's still very disappointing. Anytime guests come over who don't have an AppleTV, they never know how to use it. Having to hold down the power to turn on/off, or how to switch profiles, or had to fast forward but pushing your thumb in a circle, and no dedicated action buttons for jumping straight to netflix or hulu, etc and siri never seeming to work reliably on it. I love minimal but wish they would offer a "pro" alternative. Alas again, expecting very little from AppleTV this year beyond adding functionality to support whatever new features come to iOS/macOS such as how they had joint watching and other things that are nice to have but far less helpful that a fundamental rethinking the design.