On the contrary, the stuff Thrall AI do is “rich”.
What other game you know that you can find a thrall that once engaged in a combat, chooses to run to the opposite direction of the target not having a ranged weapon, or trying to use a slow ranged weapon with their enemies in front of them ? That is “rich”, not poor.

People love the branching narrative concept, so lets use that image.

The AI works in a branching structure called “Behavioral Trees”. While a “average” game the NPCs participating in large group spawning (like trash mobs, or city dwellers) have around 5 to 8 branched trees, and a more specific NPC might have around 10, 15, the largest branched behavioral tree in CE is around 7 (being extremely nice with the concept of what is a branch).

Your average companion in a game, not even required to be human, might have around 20 branched behaviors.

Now you look at the forums, what people are whining about ?
New maps
New weapons
New Events
New Bosses

What good is any of this if it is populated by cardboard entities ?

I dont blame Funcom for the lack of smarter AI.

I do like Thanos …