I've heard many colleges have switched to Python for Comp Sci. I've seen linear algebra and computer graphics courses done in Python, too (including writing a ray tracer). The goal is learn the concept without the language getting in the way. Performance isn't a big concern (with poor performance you can still play with sparse data structures and other optimizations).

While I imagine it was good to get familiar with writing C, even assignments for operating systems classes didn't have all of the performance concerns or strict checking that production code would, right? (but C still is probably the best choice for other reasons in an OS class)