Sry, but even when talking with friends on ts and when playing a new class you can play a lot better than they did. i was seriously shocked, too. It also shows, that they didn't really prepare for this stream, which is even more worrying.
Talking with friends on TS doesn't require half as much focus and doesn't imply half as much stress as talking in public with a wide audience and with PR-constraints. Sorry but that's not even close to comparable.
That said, I have to agree with you on the "improvised" feeling of the whole thing. Enforced by the very short notice...
I agree that they played surprisingly bad. Really bad.
But...
Look at what you can achieve alone (I'm not talking about "ingame" right now but about pretty much anything you can do in life, pick up whatever you can think of... like, for instance, answering quizzes or trivia, singing, dancing, speaking, whatever).
Same situation with your friends : (you're performing less already)
Same situation with an audience of 5 ppl that you don't know (you're performing significantly worse)
Same situation with 10 ppl that you don't know (you're performing even worse)
Same situation with 50 ppl that you don't know (you can't even start to understand why you're doing so bad when you do so well in your own bathroom)
Same situation with thousands of ppl that you can see (you're sweating all over and your brain seems to be frozen)
Same situation with thousands of ppl that you cannot see (live TV or streaming situation) - You're paralyzed
Same situation with thousands of ESO players (ready to jump at your throat or comment your every move and word).... : ??*]
TL/DR : it's more difficult than it looks. Especially if you have to hold a sensible conversation and are responsible for a camera.
Most of this could have been made easier with some more preparation but we can tell from here that ZOS staff is overwhelmed with work. Also, my opinion is that they don't play their own game enough. Not because they think they don't have to, not because they don't care, but because they're overwhelmed. For the same reason, it looks quite obvious to me that this stream was set up in emergency due to the lack of time/resources to set up a proper ESO live episode.