This is a great talk. I've been working on a very similar concept for World of Warcraft at https://github.com/agent-wow/agent-wow.
A lot of the techniques and pitfalls he talks about also aligns with my experience on WoW agents too. It's also interesting to see how agents coordinate in these kinds of game environments.
I found the YouTube video the other day and enjoyed watching it.
The agent pathing seemed to clip a bit through the sides of mountains at times though -- or maybe that is just a bug of GM camera following player?