Most of the “Mixes inspired by…” have been absolutely marvellous.
To the point that sometimes I like every single song in it. 
It is painful to add song by song to a Playlist.

This feature should allow me to add the songs to a new or existing Playlist. 
if adding to an existing Playlist, and if it finds duplicates, just display how many were skipped. An alternative would be to have a setting where duplicates in a Playlist gets moved in the order that it exist to the order coming from the mix. 
Thanks.