I want to watch it so bad. How spoilerific is it? 
Edit: Watch with no audio. I didn't see any subtitles. But I wanna hear his voice~
If you watch the stream from the very beginning, it is VERY spoilerific. But, if you just go to the timestamp that I mentioned, just to hear what Blackwall has to say, it's not spoilery at all, in my opinion. And he does sound a bit different from the party banter that we've already heard.
OKAY WAIT:
There is a spoiler, a pretty big one, in the conversation. I didn't think about it, because I already knew about it... They're talking about the Big Bad... So if you already know about the Big Bad, and you don't care, then feel free to watch it. If you don't know who the Big Bad is yet, and you don't want to spoil that part of the game for yourself, then don't watch it.