
A semester grade, in my mind should reflect overall performance. This means that if you have one bad test or assignment, it shouldn't affect your overall grade. Who knows, you could have forgotten to study, or just been having a bad day which leads to you not performing at your best during a test.
It seems as if teachers don't like to give out finals also. More often than not, teachers that I have had in the past seem to dread grading finals and would rather just give a multiple choice test to make their job easy and so that they don't spend a bunch of days grading exams.
No one likes taking finals. It is very stressful for the students, and sometimes annoying for the teachers. I think that final grades should rather be taken into account of a semester of the student. Participation seems to directly undermine assignments and final grades tend to only reflect the work on tests, which accounts for maybe one day every two weeks of class work.