I can see your side of the argument regarding GPA...however, please keep in mind that you can set your sights rather low taking easier courses and maintain a 4.0 GPA. For example, suppose I simply take the bare minimum courses to graduate while another student takes harder courses (i.e. calculus instead of "review of math II" or advanced physics instead of "Earth Day Science"). Of course, courses being hard is a rather subjective interpretation.
At the end of the course, the student taking the harder courses might receive 2 Bs while the other student may have earned 2 As. Now, when some college is evaluating the students, they may only look at the GPA and not the coursework. While this is not a college I would prefer to attend, some students might be overlooked.
As far as "partial" grades, I actually prefer this approach if done properly. When a student gets a "high" B and another gets a "low" B, they both equal 3.0 at the end of the course. At least the partial grades help weigh this properly. I do agree that the "4.5 for an A+" is worthless....it is impossible to master 100% of anything!
Of course, my argument assumes the teacher is applying the system properly.
Everything you said makes sense except for one thing.
IT ISN'T FAIR!
You can't just up and change the system like that. Not all schools follow that system. How do you adjust for applicants from a school using the old system against applicants from a school using the new system? And how do you compare GPA of an 18 year old applicant to a 30 year old applicant from the same highschool? Not to mention different highschools.
But even if there is an equalizing method for comparing the two different systems, I would still be against it. The reason....its just silly. Once you get to grad school, they get way more realistic. It's A, B, or incomplete. No half grades, no extra credit, and no one gives a * what your GPA is. And you beter not get incompletes because they will pile the work on 3 fold. In grad school you either get ignored or you graduate. Then after that you either get a job, or you get a phD. Real life doesn't have 9 gradations. Real life is thus: good, OK, or fired. And OK is only acceptable if it doesn't happen every day.