A short while ago I was in my son's yeshiva for their annual gala siyum. Close to 50 mesivta boys finished Baba Basra, another group finished Sukkah, and another group finished reviewing Gittin again (which the yeshiva learned the previous year). I am happy to say that my son was not the only 9th grader who managed to get through all 175 blatt of Baba Basra, the longest masechta in shas. The yeshiva he attends is not on the far right-wing of the chareidi world; it has a mix of boys from the Far Rockaway and the Five Towns. Many of these boys will go on to professional careers of one sort or another after their yeshiva years. Yet, it is still a "black-hat" yeshiva in the traditional mold.
For all the discussion of the importance of "rationalism" and the touting of modern orthodox hashkafa, the bottom line is talmud Torah k'neged kulam; the achievements in limud haTorah of the yeshiva world are unparalleled in the modern orthodox high schools. The same level of accomplishment is simply impossible in an environment of co-ed classes and a Talmud period of an hour a day.
Sure, there are problems with the yeshiva system. The cookie-cutter mold disenfranchises many students who are just not cut out for the system. Students' questions in many areas are not addressed properly and lead to superficial conformity without depth of commitment (i.e. towing the party line). But these problems are not solved by the modern orthodox education system and a good case can be made that they are even exacerbated. Greater openness to secular knowledge and culture has not proven itself to be a more effective barrier to assimilation in and of itself.
For all the talk of kids at risk and the weaknesses of our institutions, I think once in awhile we need to take stock of our successes as well.