There's a big gap between "not all that hard" and "something you have time to create from scratch for every problem on every exam in all of your classes every term".
In general, creating good, well-balanced problems isn't easy! And many of the "classic" examples are classic precisely because they incorporate just the right blend of concepts in an unusually simple package. That's not easy to duplicate, if it's possible at all. (I do my best to write exam problems that way, but it can be a tortuous process.)
In general, creating good, well-balanced problems isn't easy! And many of the "classic" examples are classic precisely because they incorporate just the right blend of concepts in an unusually simple package. That's not easy to duplicate, if it's possible at all. (I do my best to write exam problems that way, but it can be a tortuous process.)