While it would have been nice for them to have an additional episode to use for the plot, I actually liked this "episode". Mako and Prince Wu continue to make me laugh, and it had been so long since I had seen the earlier Books, it was kind of nice to see a quick overview of that stupid romance triangle and how far everyone had come. I had also forgotten how Amazing the fight animation was, oh my God. I guess I really will have to watch those episodes again at some point.
And yes, the conference call between all the villains was hilarious. I'm surprised they had Movie!Unalaq instead of actual Unalaq for their clip, but maybe they couldn't find a scene that worked for what they were doing.