especially group playlists. i think it would help if we could assign playlists to channels like with other sift posts ... also, a continuous play button would be nice;) here are some of the great group playlists out there which you can participate in:

http://videosift.com/playlists/eric3579/Sifters-on-VideoSift
http://videosift.com/playlists/Eklek/Lets-make-art
http://videosift.com/playlists/Krupo/PQUEUED-with-9-Votes
http://videosift.com/playlists/gorillaman/British-Humour
http://videosift.com/playlists/rbar/TED-talks

edit: another suggestion would be to set default playlist listing order to "most recently updated"