Actually, at my department (a "top-10" school for CS), for each course we TA, we're expected to write at least one problem set and come up with at least one question for each exam given. There are also half-courses on intro to Unix or intro to C++ that are taught entirely by grad students.
I suspect the OP was teaching an intro-level course, designed to get freshmen up to speed on basic linear algebra, filling any gaps they might have had in their high school curriculum.
What I'm taking away from the article is the ol' KISS prinicple.
I don't see why building on an RDBMS necessitates added cost, though. I can think of at least two production-quality products that are free, and depending on the application, using the structure provided by database tables and SQL queries can actually be simpler than using a mishmash of hashtables and XML files.
I suspect the OP was teaching an intro-level course, designed to get freshmen up to speed on basic linear algebra, filling any gaps they might have had in their high school curriculum.