Being lazy here and not searching for existing courses already, I suggests data analysis or introduction in Statistics (such as probabilities and distributions). Both will look great and will be informative with Wolfram language. I will start teaching them soon in first and second level of BSC, so if they are not here, I will create them myself :) I love the certificates and exercises idea.

Complexity Science seems to be advancing frontiers in many conventional subjects. For example, network (graphs) have become important tools in chemistry, biology and sociology to name a few. Ergodic theory, Tsallis entropy and non-Gaussian statistics seem just as important. While it may be difficult to develop a curriculum, Thurner's recent text, Complexity of Complex Systems, might provide a starting point.

A second suggestion related to the "physics" idea Carl mentioned... Squigglology. That's what I call the study of how to interpret and repurpose a variety of notations found in physics texts. Wolfram Language treats many of these cogently, once you 'break the code'. Tensor notation is a difficult but notable example.

I would really like to see a series of three or four beginner/intermediate/advanced really challenging classes on the evaluation process and term rewriting that underlies the surface appearance of the Wolfram Language. Each of those classes should be difficult for students at that level and require substantial work by the student during and after the class with exercises to do and answers to compare their work against after they think they are finished. The result of each of those classes should raise the student's skill to an entirely new level.

In the future when a user makes a mistake as a result of not understanding the evaluation process someone should direct them to the appropriate class and after the student works through that class they should understand exactly why what they had done was incorrect and how to do it correctly and how they will never make a mistake at that level again.

I am hoping that users will be amazed at how much they learned from putting in the work on these classes.

Oh yes, they should have the (Linear) Algebra equivalent of the calculus course as the college freshman classic duo :D
I use this quite a bit to look up some of the more mathy stuff: https://www.wolfram.com/language/fast-introduction-for-math-students/en/

Hi Katja, thanks for the message. Here are two suggestions: Developing GUIs in Mathematica and Engineering Mathematics