I do not think m1 is a waste of time. We all know what is the meaning of " taking a course" in most of Chinese universities. It is absolutely different from understanding a course. M1 gives you a very good preparation for further study. It is the forth year of French university, but that's not equivalent to say you learned the courses in your undergraduate. More rigorous and more difficulty. Take a look at the first four chapters of SLP, if you learned it and think it is easy, then go to m2. Or I think a better choice is to apply for m1. Also,It is relatively easier to get a decent ranking. I myself once thought m1 is not that hard. But after the first week, I was totally wrong. I still have a long way to go in order to really know the staff.