First, on Fallout Tactics, I always took control of the members, and lead opponents into ambushes and crossfires, so I never really had that problem.
Second, you guys have no idea the difficulty to making a good AI system. Having programmed (although very rudimentary) video game AI, I can tell you it is not an easy feat, more so these days where the environment is very dynamic and there are many variables. It consumes a lot of system resources, as the bots are constantly checking distances (we have had our system crash several times because of it). Lastly, it is super expensive to buy an AI pack, or take the time to create one.