Interesting article.
My alma mater has been doing something like the described "partially structured recruitment" for years - including when I rushed. Each PNM visited each sorority for 10 minutes, followed by about 8 hours (over two days) of "open houses" where she could go back to any sorority's rush room and spend as much or as little time as she liked. During round 2, a PNM could attend "informal rush" anywhere she had been invited back, again spending pretty much as long as she wanted with each group. That evening there was a more "traditional" theme party. Next night was pref, followed by bid day.
The system worked well with our campus culture (Northeast school, 5 NPC sororities), but the big danger was that PNMs would see each group for only 10 minutes, which equated to one brief conversation and a skit - if a PNM didn't click with her rusher and/or didn't like the skit, she might not go back to that sorority even though she might have fit in well there. PNMs were also told that "informal rush" was optional and whether they attended or not would not affect their chances of getting a bid - yeah, right.
I have no idea how we got the green light to proceed with such a non-traditional formal recruitment back then... but I'm glad NPC is finally acknowledging that the one-size-fits-all, you-must-have-fully-structured-formal-recruitment-even-if-there-are-only-two-small-sororities-on-campus approach isn't necessarily the best, and is allowing for some alternatives.