Well, it is pretty obvious at this time that the one way art design is preferred, since it is by a definite majority (75% of those polled). Looks like I got it right from the outset. Preferences are pretty evenly divided between #7 and #8. If #8 is chosen, many people suggest 2 quotes. I will probably end up with 2 paraphrased statements instead, but I honestly don't mind that. I think I am leaning in that direction.
Now that the design is decided, I still have some questions on the court cards and aces, and how to make them unique. For the aces I was thinking I could inscribe the art within the suits, in something like this:
I could of course make them slightly more ornate, but my cards might be complicated enough at this point.
As for the court cards, I think I could add a border, either just on the top and bottom, or all around. The border could try to contain classic card elements, such as having the Jacks border have spears/halberds, king having swords, and queens having flowers. The suit could also be in the border. Any other ideas come to your mind?