While I do agree that New Mutants (vol. 2) and the early Academy X run are not strictly necessary to understand and enjoy Kyle & Yost's run, I think it's fun to experience the dramatic shift in tone from those early DeFilippis/Weir stories to the post-Decimation stuff. I think it all flows pretty organically and, as much as I love the original New Mutants, I think the book benefitted immensely when the focus shifted 100% of the kids.