Thanks for the feedback Rousselle and Giovanni, I actually got the same feedback on the skin tones from a couple of other people.
I have tried the white skin like you mentioned, but I did not really like the result. So I have made the facial lines a bit darker and the skin tone a bit lighter.
I think it is an improvement.
I also made the same skin color changes on the jack of diamonds, along with some minor color changes on the body. I also added some details and replaced the eyes that match the style of the queen of diamonds.
PS: Yes your Evil Deck is also made in flat design style, it is a great original deck =)