I know this is not an easy thing to do, it will require a lot of planning and arranging and coordinating. If parents are unhappy with the way their yeshivos are educating their children, and by this I am specifically referring to the HASHKAFOS of the yeshiva, which include rejecting prospective students for stupid reasons, or pressure from a few parents, why not take the kids home from school for english classes (of course those yeshivos that dont teach english – and I can tell you what an avla that is as having worked as a guidance counselor for a program offering Associate Degrees to heimishe yidden as a means to earning a parnassha and supporting their families, but that is for a different topic, different subject, different time) for several days. You can be sure the silence in the classrooms will be deafening. You can be sure the administrators of these yeshivos will want to get to the bottom of whatever it is that is bothering the parent body. Yo can be sure the word on the street about that yeshiva (and there will be all sorts of misinformation flowing) will be enough to force the hands of any administrator.
I think how much time and energy, those who complain about yeshivos and their administration, are willing to commit to resolving these issues will say a lot oabout how much they really care or they are just blowing a lot of hot air.