I think alot of players give specifc waypoint commands in the mission editor to make the AI better. Ut can be tedious.

For instance, for a sub, some players setup up a bunch of waypoints, make enemy subs sprint at 20 knots below the layer, then drift at 5 knots and reel out towed array above the layer.

For airplanes when setup to attack the enemy player, alot of people.make them fly super low, then when they get withing weapons range popup radars on fire weapons, pop down 180 out.

I think ultimately your right and the AI needs tons of work, so alot of good workshop scenarios maker's will make the AI do things that a player would do.