Request for Others and SOPAC
Over the past few years we've taken advantage of having a catalog we can tweak and change. Recently as we've been able to store more data outside of the ILS we have gone the route of making our catalog one of our main development platforms.
However, staff still had to go back to the staff client for the ILS for some functions. While many of those functions don't really make sense as part of the catalog, requesting items for other patrons was one that did. Having full control over the search and what fields are indexed created a back and forth between the client and website for finding things.
We just rolled out the feature for staff so they can request for others via the public catalog (if they have the permission). Its a feature I'd recommend looking at implementing if you are working on an opac replacement or other catalog like feature.
Just one more step moving more non-inventory things to the drupal/sopac side of things rather than the ILS.