After the views conversion of the admin/people listing, there's some cruft left behind that could be cleaned up.
- Extending $options but $options doesn't exist anymore
- Not using user_load_multiple()
- Unecessary loading of user roles with a query per user
- Loading unecessary data in the query.
See #1932068: People Admin Table Missing Labels and #1751274: Implement user_roles as a field on user entities, you can basically re-use all changes to that function from the last issue and additionally remove the $options line from the first. Possibly even more that I haven't noticed yet.