I've found that third party applications like Orion are far better UI wise than Twitch. The twitch web interface always felt clunky to me. I don't know how they managed to mess up the interface but Orion (a desktop app) plays the video streams far better with no weird lags or stutters.
The only complaint I have against the twitch UI is recent, and that's the idiotic "unread message" indicator every time I log on trying to sell me prime. No. Fuck off. At this point I'm less likely to buy prime because of this.
Other than that it does everything I want. Shows me all the active streams of a game I like, lets me follow people I like and get alerts when they're streaming. And the video content plays pretty well. My main remaining complaint is that they'll run adverts over active content - which is infuriating.
You can get the source here: https://github.com/alamminsalo/orion
or just google "Orion Twitch" if you want compiled binaries.
I have no affiliation with Orion, just a satisfied user.