I'd like to see a cooking teaching app that allows users to work through a recipe in varying levels of detail. For example, consider a Lasagna. A lower level recipe may use ricotta for a quick and easy version, a higher level might explain step by step how to make a bechamel, and the "hardest" level may just say "make a bechamel".
As a user, being able to select a difficulty level and see the differences not only allows me to learn new techniques at a pace that suits me while experimenting, it also teaches me more about the dishes and how recipes can be changed while keeping the spirit of a dish, or the flavour profile.
The best cooking videos on YouTube, people like J Kenji Lopez-Alt and Chef John from Food Wishes dot com, tell viewers what's truly necessary, and what's not. What "makes the dish" and what they're replacing in the recipe themselves because they ran out of the proper ingredient. I've learnt so much from this sort of thing, and am far more confident both creating my own recipes and modifying existing ones, having been a to-the-letter recipe follower for many years.