How typical is this? It doesn't match my Canadian large public university experience, but maybe that's because I took clinical/tech programs? Or that our class sizes can be bigger? What would one prefer, classes of 300 with a full professor, or 30 with a grad student?
On the topic of large class sizes, there is definitely room for improvement in the US system; being at a poorly-funded mid-tier public university, we had several courses that were so large that there were overflow rooms with a camera pointing to the main lecturer in the main room, and these were lecture halls that could easily hold 400.
I guess that given the breadth of possible options when it comes to American universities this is one area where YMMV.
For example, the introductory engineering classes you typically take in your first year are large 300+ classes taught by professors with lectures 2-3 times a week. Additionally, TAs (typically grad students) would hold smaller sessions for those classes with maybe 30 students each.
Once you move into more specialized classes the size goes down significantly and are all taught by professors.