I think that everyone generally should create and design their own Finitate State Machines for those more complex game engines, but as for stuff like NNs and GAs... that can be a bit daunting for some, even myself who is a bit more familiar than a few people about using these in game AI.

Also, Itenc to think that hybrid are the best alround though. You mix methods. It realy gives you more options when you do that. And some rather interesting results when experimenting.