This leads me to my final point: the Amazon Echo.
Let's get the first thing out of the way: Pandora Premium doesn't yet have support for devices like the Amazon Echo, though the company says it's coming soon. That's a bummer.
As I said before, I love using regular Pandora on my Echo, and I think it represents a huge opportunity for the company. I listen on my Echo when I'm doing other things, particularly cooking or writing. During those times, I don't want to actively engage in looking for music, so I go for Pandora's lean-back feel.
But what would be amazing is if, during the midst of this, when I hear a song I like, I could instantly tell Pandora to save it to "My Music" or to a particular playlist. That would be a game-changer for me because it would enable passive discovery of music in a whole new way.
No doubt when Pandora Premium comes to Echo you'll be able to do this, but Pandora has to fix the radio licenses issue first. If, when the wrong "Can't Stop the Feeling" pops up on a Pandora station, Pandora just tells me it can't save the song, instead of suggesting a similar version that it can save, that's a huge blunder.
Overall, I still have hope that Pandora Premium can be the first service to completely nail the combination of lean-back and on-demand, but its initial rollout has a few quirks that make it fall short.