I agree with your assessment. I'll decrease the difficulty in Simulation mode further, and see if I can introduce new features more gradually in the first few missions so the player gets experience at a steady pace.
Please know that I will be finishing my current project before coming back to SBMS. This might take a while, and I would have to refamiliarise myself with the old development environment and I will probably want to make several changes to improve the game, including adjusting several missions rather than just mission 2, and updating the GUI.