I regularly use a different account for watching YouTube which is also the account I pay for Premium on. I simply want to use that account only for YouTube and my main Gmail account that I use for everything else as the Google TV account. It worked fine before profiles were added; which I understand is a useful feature for many people but I have no use for them. The only workaround I've found is to use a custom YT app like Smartube TV Next but it doesn't just function as YouTube so things like redirecting from the dashboard and YT Premium content don't work. Switching accounts every time I want to use YouTube is a real hassle and I always forget to change back so my GTV recommendations are all over the place. Not to mention if someone else wants to use their YT account it's the same issues. Just messy. Should just be an option to use an account just for the app like every other non Google app.
It's maddening. And you can't even set a default. So every. Single. Time. I try to cast something out pops up and makes me pick an account. So I have to find the remote to hit enter.
My problems started back when G+ showed up and Google tried to make everyone change their YouTube accounts to be their real names. I refused, and my account got converted to a "brand" which has pretty much just complicated everything since.