Good suggestion, thanks!No I actually quite liked them.
Are you still doing 4 different decks, or one with all 4 designs on it?
If you are doing 1 design, You might want to put the sun and moon in Bottom Right & Top left corners, so one moon will cover both fall & Winter, while the sun covers spring and summer. Also, if you get rid of the lines, you could make the gradients blend better if its not too much work.