Shame on Apple for ruining a useful feature. I hope they fix it SOON. Stations cannot replace a playlist because you can't control the order in which episodes play. Be sure to tell Apple how you feel about this at Product Feedback - Apple
In the meantime, I have found a workaround for playing my podcast playlists!
Make your playlist as usual on your computer. Give it a distinctive name, and then sync your iphone as usual.
Now, on your iPhone's home screen, pull down from the center of the screen to bring up the search screen. Type the name of your playlist, or a few distinctive letters from it. Your playlist will appear in the search results. Tap it, and it will open in the Podcasts app, and the episodes in the playlist will populate the Up Next list, and they will Autoplay!
Unfortunately, if you pause your playlist and open other apps, or even have your phone sleep for a while, your playlist will again go into hiding, so you will have to do the search all over again.
But at least you will have Autoplay of your carefully crafted playlist for the current session.