Not sure I'd agree with you on this, though -
Madoka Magica might have wider appeal than the likes of
Nanoha, but as someone who used to put together themed screenings for a society myself, I'd argue that it isn't the best example to use to showcase the magical girl 'genre', since it's basically a complete deconstruction of said genre.
We did actually show Madoka at Aberanime's 'History of Magical Girls' night (which was just a collection of first eps), but we felt it was more appropriate as a show to end on - a darker twist on all the tropes established over several decades, many of which featured in the earlier shows. I believe the lineup was
Mahou Tsukai Sally,
Creamy Mami *might have pushed for this one, but hey, it's the first 'magical idol' show, and the first of many produced by Pierrot*,
Cardcaptor Sakura, Nanoha and Madoka Magica. Huge shame that there wasn't also space for
Sailor Moon (and part of me wanted to see it shown precisely BECAUSE one opinionated member said he would walk out if we screened it), but the committee thought Cardcaptor Sakura would be a more popular (and arguably equally important) choice to represent the 90s.