Yes, letter grades should become pass/fail, due to the way that if effects a person/student. We got learn that pass/fail's higher criteria will boost many students mind as well as let them know that they did actually pass the assignment. Tell me do you really need the F and/or A?
We have gone so far in trying to encourage self esteem that we have worked against ourselves. Someone who has done a lot of work in a subject area does not want to just see a pass or a fail. He or she wants to be credited with a nuanced grade that says how well they have done.
Letter grades should not be replaced by simple pass/fail grades. Letter grades give children and their parents more feedback, by creating a scale. If someone passes with D-level work and another person passes with A-level work, yet all they receive is a "pass" grade, neither one will be quite clear on how they were doing. Any scales, such as percentage grades or letter grades, are much better at giving a clear picture of how a student is doing in a course or subject. Lower grades can be an encouragement to study more; while high grades encourage and reward students who are excelling in subjects.