Make it actually possible to turn off the HTML5 player
I have no sound in the HTML5 player. "No problem I thought, "I'll just disable it." I can click the switch, it directs me through the 'Why do you want to disable this' dialogue, reloads the page and starts the video, with HTML5 activated obviously. So now, I can just not use Twitch. Which, frankly, sucks!
(On a side note: Maybe it's possible for this page to not delete everything you wrote on logging in)