Modern music can still be analyzed for its valid musical elements. Whether you believe rap is music or not, there is a rhythm study that can be done with good rap. As an additive to the music curriculum, I think that's fine. As a replacement? I think that's a negative. What I do find interesting is how dismissive people are of rap as "non-music" and the standards they seem to think are required for music. There's often this west vs. everything else perspective in music that seems to think lesser of the musical norms of cultures that are not adherent to western standards. African styles of music are highly rhythmical with less emphasis on the melodic structure but based on the comment from Jerry Garcia, rhythm and meter alone are not enough to classify it as "music." There are various Asian culture that use non-typical scales and tones compared to the west, and again it seems like often elitist will classify it as cultural, but not musical. I consider that way of thought a major failing of the current curriculum. Music is music, and the quality may vary, but there is a way to analyze and a value to analyzing all forms of music, even if we don't get it.
Adam Neely has a nice video about this and the cult of the written score. How we put up certain styles on a pedestal and ignore what "music" is, and the validity of current music and scores.