Faces functionality is terrible. Photos is worse than iPhoto, and there seems to be no concern about that from Apple.
Faces was added to iPhotos at least a decade ago. It was great. Auto-identification wasn't the best, but the functionality for adding faces was useful, directed by the user, and progressively improved the collection.
The current functionality is ridiculously bad. The auto-recognition finds only a few photos, then gives up and says "there don't appear to be any additional photos". In fact there are many more photos of the individual. The user cannot direct the search in any way. All that can be done is to manually add faces to a photo. Even when obvious and unobstructed, Photos doesn't even know faces exist in a picture. "Faces" is terrible, and so much worse than iPhoto that the mind boggles.
Why has Apple allowed this formerly very useful feature to become effectively worthless. Photos from its inception has been a downgrade from iPhotos.
The only thing that seems to change in Photos is the file format, which requires the library to be updated -- without warning or option. Open the application and, hey!, you get to wait for 5 to 50 minutes or more before you are able to use it. How is that considered to be acceptable?
Apple software...it's decent when released, then abandoned to languish in mediocrity.