Sims have a valuable role to play, but their key drawback is unavoidable; they can only represent the expected. All of the software models how we expect the aircraft/ weapon / opponent / etc / etc to behave. Whilst the models no doubt represent our best assessment of what will happen in a given combination of circumstances, they are by definition framed by our pre existing expectations. In other words there are no surprises, whereas in real life, experience tells us that surprises are still plentiful!