Hi Victor:
Einstein was quoted as saying: " Keep everything as simple as possible, but not simpler".
Simple is good when it accurately reflects what you are trying to measure. Some courses have many components that make grading a convolulted process. Even though, these courses assessments can still be based on a simple premise.
Of course the goal should be on complete and accurate assessment. If that can be done in a simple manner, that's great! But care should be taken that we don't inadvertently undermine the students perception of their performance because of a weakly constructed grading assessment. This is really something important to consider in the development of assessing student performance.
Regards, Barry