I think that's a good idea. It would make for some interesting talks from time to time. I think there would probably be some episodes I don't care about, but others might give cool insight. So, I'd watch from time to time.
However, I think the problem is that he works a full time job. It's my impression that Day9 doesn't have the time to prep for shows. So, a show like this would either have to be completely improvised or it he probably just couldn't do it. There are often times during the decktacular where he stops to gather his thoughts before talking about a subject. It might be a little jarring if he made a whole video series where he's constantly doing that
Still a good thought and maybe if he has more time in the future he could give it a go.