Tom, I don't think your example is quite right, as Far Cry only used very simple state machines and didn't do anything very sophisticated, as you can see for yourself reading the script... simple state machines, events handling and "pipes" of goals to accomplish. While I don't think I have the right to comment the code, I doubt your problems running it are AI specific.

Characters in F.E.A.R. use planning, which is in my opinion more sophisticated than what was used in Far Cry. You can read a few articles by Jeff Orkin in AI Wisdom books, I beleive they've been using this technique since No One Lives Forever.

As of pathfinding and sensory response being the bottlenecks, I believe its genre specific... while using scripts to write the pathfinder wouldn't be too cleaver, if we're talking about a bomberman clone, I don't think it would matter that much if it can boost the productivity and have a prototype ready sooner. Once that's done, you can profile and improve what the true bottlenecks are.

Cheers

Eric