Not exactly. You are correct in stating that the Comprehensive Curriculum Program does apply to the bottom of the class as well as a mandatory extra semester for the lowest ranking students (for added instruction of necessary skills per the school and for higher bar passage rate practically as those students are forced to take the February Bar). However, this does not necessarily mean that students in the Comprehensive program do not fail out. In fact the Comprehensive program, at least four year version, forces students to take mandatory classes throughout law school in specific harder courses during the second and third year which are tested heavily on the New York Bar Exam such as Corporations, Wills and Trusts and New York Practice.
The Plus side is that this is generally very good preparation for the bar and the schools passing rates have gone up as a result. The negative is very little ability for students who do poorly or just bellow the curve in their first semester to specialize in any area of law or take any classes they feel would interest them. Further, by forcing the lower half (it is almost about half), of the class to take the most difficult courses these students are almost guaranteed to remain in the lower end of the class. Consider an example of a student in the upper half of the class taking Sports Law as an elective during her second year as well as Corporations. Then a student in the program who must take Corporations is precluded from taking Sports Law and then must take Wills and Trusts (a much harder class) instead. The lower ranked student will have a much more strenuous workload. This is especially daunting during second semester of first year when grades are most important for achieving employment especially in New York City out of a lower prestige school such as New York Law. Students in the program already have the disadvantage of lower first semester grades now coupled with some of the most difficult courses the school offers during their second semester.
In general students in the program do not tend to fail out in droves as is the case in most law schools after first semester (your tuition is to valuable to drop you), however many do drop out second or third semester. The realization that they will not be able to study what they are most interested in or specialize in anything (which would help greatly in getting a job out of NY law if not top 10 in the class), and likely remain in the lower half of the class due to being compelled to take harder classes then their piers and resulting career implications cause many students to reconsider law school.
Hope this sheds some light on the program and implications as well as answer your question.