You may be right, maybe the developers at Sony just screwed it up on accident. But either way, one of the most-basic features is broken and end-users have no way of knowing when it will be fixed, if ever.
But from your responses, you must have an inside source, or you just have more faith in Sony than I do. Myself and others have posted on the "Sony Community" support message board about this issue of the firmware update killing the YouTube for TV app, but the only official response in the thread has been from a moderator suggesting to reset and the player, and/or returning the settings to default.
Even if they are hard at work behind the scenes on improving it, I don't see how releasing a firmware update to take the YouTube for TV app down completely was an improvement. I don't like to download unnecessary firmware updates, since there's always a real possibility of bricking your device, but I downloaded this one because I was specifically hoping it would fix the YouTube for TV app to allow me to sign in. So it left a bad taste in my mouth when the first thing I tried after the update was the YouTube for TV app, and instead of being improved, it had been killed.
And what's up with none of the Vevo music videos showing up on the remaining, standard Sony YouTube app? You don't have to be a paranoid conspiracy-theorist to realize that there is definitely something going on behind the scenes there.
Anyway, I just bought a second Panasonic BDT-DMP230 to replace the Sony S590 in the living room since the new YouTube app for the Sony never worked right the whole time I had it...it would never allow me to sign in to my YouTube account. And the Panasonic also allows me to view captions on Amazon instant video, something the Sony players inexplicably lack. These two problems are very unfortunate, since the S590 is otherwise a great player, and works better for DLNA streaming than my Panasonic.
Edited by Edgar_in_Indy - 10/7/13 at 6:49am