Hi,
playlists are an excellent feature. However I find it is now a victim of its success. Having looked through the list of public playlists, I copied about twenty that looked good. This now leaves me with a lot of playlists. I deleted a few, but would like to be able to order the playlists and also be able to merge them. I can merge them by selecting each video and adding it to another playlist, but if there are several pages then this is too tedious. So some additional features would be helpful:
allowing multiple selection of videos in a playlist to enable you to copy them into another playlist
allowing merger of playlists, or mass copy of all the videos in a playlist into another playlist
allowing mass delete of multiple selected videos in a playlist (at the moment you can delete the whole playlist, but not several videos in a playlist at once)