Hire a New Team to Work on UI
As a viewer who only sparingly watches any stream other than the small handful I like and would actively not like to see a bunch of streams I don't have any interest in, every single aspect of this UI update is terrible, inconvenient, ugly, obtuse, and otherwise was a bad move. When I go to a channel I do want to watch that's offline, I'm assaulted by whatever person that streamer is hosting and have no option to either stop the hosted channel from appearing or to remove the elements I don't like from the offline page. The offline page is hideous, the background to this little tiles thing is blindingly bright, and if I pause the hosted stream, like I do instantly every time, and scroll through those tabs? When I come back around the video starts again. Literally the only thing I want to see or have ever wanted to see when I go to a stream that's offline is the offline image of that streamer.
The blog post that led me here said that community and streamer feedback was involved in this process, but I find that hard to believe given how this type of update has traditionally gone over on every single platform that's done it. If you had actually taken feedback from people, you would have realized that no one ever likes UI updates, they simply tolerate them long enough to become the new (worse) normal until the site redesigns again, and again, and again, and eventually becomes so utterly unusable that people leave for more user-friendly alternatives. This is why at a certain point in Twitter's endless tinkering with the layout of their site, Tweetdeck became a thing; it's a simpler, more straightforward way to access the same content minus the UI problems on the main site.
BTTV's options did a lot of that simplifying and easing for me before the update, and it's an incredibly common and popular extension for both streamers and viewers because of this (and the emotes). I was positively GIDDY when I found out I could stop seeing hosted streamers, for example, or move the chat to the left of the screen, or change the background color every other message to make the chat more readable. Y'know, quality of life features Twitch should already have and doesn't for some reason. Probably because the team that would be implementing those QoL features was too busy for a year creating a new layout, if I had to guess. It doesn't help my opinion when the general consensus seems to be that there are obvious features missing, which tells me that a year was absolutely not enough time to get this completed and taken live globally.
So, here's my idea. Fire everyone involved in this decision from the top down, hire the BTTV people, and let them clean up the last team's mess. I realize you probably paid some graphic designers a very good amount of money to make this for you. I mean it took a year! Unfortunately, the end result is awful. Take it as a lesson and hire someone with any amount of talent or understanding of the platform to fix it.