I’ve been wondering too why several Ivies are moving to SAT IIs being optional. I haven’t come across a good explanation but perhaps it does have to do with the new SAT format, or maybe it’s just that the schools want the flexibility to accept exceptional applicants who for one reason or another don’t have SAT II scores.
Regardless, to me when highly selective schools say “recommended”, for the most part I take that to mean “required” for those who want a realistic shot at getting in, perhaps with some exceptions for highly recruited athletes or others who fit institutional priorities.