I'd argue more of the issue is with the zoo management not the AZA management for having misplaced priorities in collection planning, and I wish more Zoos would look at how common species are nationwide to choose species most in need of additional holders, such as going with a different callicthrid species that's AZA managed instead of the Golden Lion or Cottontop Tamarins so many zoos have, or going with a different Spheniscus species instead of African Penguins. Those are decisions that the zoos make, however, not the AZA. If anything, I'd argue the TAGs need more power to enforce which of similar species zoos can keep- in an effort to more evenly distribute holding space amongst species with similar requirements.
I have heard many curators are only going by the SSPs and avoiding anything that isn't a program species. Many of the odd decisions are made at curator level, and frequently have more to do with curator preferences than AZA recommendations. It is not at all uncommon to see major collection shift with curator shifts.