When one's discard pile contains a lot of cards, using harbinger card is hard. All the cards in discard pile overlap heavily, making one don't remember which is which or which is selected.
How about do a sort, and display the discard pile like displaying the cards on hand?
Seconded!
It's particularly bad in Black Market games where I might have a couple dozen different types of cards in my discard pile. It's tough to guess from that thin strip of card art what you might be getting.
If the cards could be pulled out/magnified as I pass over them with the cursor that would do it for me. It seems odd to sort them, especially if e.g. you know you just played a certain card you want to choose. I don't like just seeing the edge strip either.
On a phone or mobile device, it's even worse. The picture of the cards are tiny, and sometimes upside down, at least on my android device