Further updates....Court cards without the wavy lines in the background look better after further introspection.
They do look better without it. I'd recommend two possible options from here:
1) Since you have the space, enlarge the artwork a bit. Alternately...
2) If you liked the background idea but felt it was too cluttered, perhaps some simpler, less-detailed light background art to act like "framing" around your characters would look good? It could even be as simple as a few small lotus blossoms or a similarly simple design here and there, just a little something to fill some of the white space.
Either way, insure that you push the indices DEEP into their corners. The closer they are to the edge of the card, the less wide a player needs to spread a hand of cards to read them, helping to prevent accidentally flashing one's hand to an opposing player. It's hard to tell what the precise index placement will be without showing the die lines on the artwork.