I'm beginning to warm up to that back, maybe it isn't so bad after all.
About the indices: I agree that they might benefit from an outward move. I would aim for about halfway between the edge and the courts frame. I also agree that the space between the pip and the number/letter is a little bit on the small side.
The font looks good, although that Q might be hard to get in the right place, I tried a similar font with my (unreleased) deck, and could never get it right where I wanted. I didn't want that long protruding thingy to touch the frame of the court. I think the difference in width between the J and the Q made it difficult to get right, for me.
About the box: I'm no Art Nouveau expert, and you might not even have aimed for that period with this deck, but when I look at "art nouveau" images they often look overly decorated. I think I like your box, but judging from what I've seen It doesn't seem to be very "Art Nouveau".
About the AoS: It now looks much better, but it still needs something more, that extra pizazz, to really make it shine.
I would like if the courts could have the larger pips inside the frames, as the classic bicycle deck. I think it would add just the right amount of color.
I think that adding the pattern from the back was a rather nice touch, but it made the hearts and diamond courts kind if blend in with the pattern too much, maybe look into that.
good luck and keep up the good work.