Just to update... I opened up my mobile app and browsed to Daily Mixes a few days ago. My missing playlists had been added back! My favorite go-to mix was back with the same flavor and reference artists.
Daily Mixes is now (finally) showing up on the desktop app, too.
Hopefully this was just some glitch as they work to build the service and my mixes won't be taken away again.
This is the first time I've been annoyed enough to post to the spotify forums. I had 3 daily mixes, and then 2 of them dissapeared, including the one I listened to most. I had listened to the mix for a few hours several times the week it dissapeared. What happened? You should be able to favorite a mix or something. Or even better, you decide when a mix has worn out it's welcome and then do a 'reshuffle' on the unfavorited playlists to see if spotify has come up with anything new.
It's bizzare that spotify took away a playlist I was actively using and didn't replace it with anything.
I also just lost a couple of my daily mixes including the one I had been listening to the most. I just listened to it for a couple hours yesterday and now it is gone. I'm down to 3 mixes from the 5 I had yesterday and the three I have now are very similar with much less variety. Frustrating. We need a way to save or pin the ones we like. Some type of control. These algorithmic features are awesome, but Spotify is my music library and I need to feel some level of control and ownership also.