Do you have any training horror stories as a writer or as an employee?
I read this and I couldn’t help but think of a game series that I enjoy playing created by Naughty Dog called Jak and Daxter. The first game is really simple and easy but as you move through each level the game gets more advanced. The next game builds on the fundamentals you used in the first. I still haven’t been able to beat Jak and Daxter: The Last Frontier but heights scare me even in a game.
My point is, nobody would expect a child to do algebra without learning basic math skills. Why should any other skill be any different. Yes, it may be slower but the employee, student, or customer will be less frustrated and more productive. A really quick side note: make sure to update your scenarios to suite your user needs.