Haha, you called me out on the KS and JC faces. Ya, the jack I just tweeked the Kings face for; it still needs development. The spades are supposed to be frowning and glaring while the zealous diamonds are supposed to be serene/contemplating. I considered closing their eyes like they were praying, but was hoping to keep one-eyed royals and suicide king a part of this deck. I suppose closed eyes still count as long as there are two of them visible.
Each suit uses a single shape that the entire family is built off of. In the diamonds case it is a V shape which is also the icon that each family member holds, (like a religious symbol).
For Spades it is a sort of backwards L shape to make them somewhat boxy, additionally they are the only family with armor, in the form of the solid filled lighter blue panels.
Admittedly, I've found it hard to visually represent Acumen for the Clubs, I've gone with giving them more gilded edges and lighter clothing to represent wealth or affluence.
I'm sort of on the fence about removing the theme names. On one hand I like the subtle differentiation they have right now, but I don't want it too arbitrary.
You think the faction idea can be interesting without giving each family a distinct "strength"? I like that it is more up to the individual user to imagine the four families that way. Or just making the strengths even more abstract, like serenity, devotion, etc...I dunno...
Perhaps you could go for simpler concepts. Zealots aren't known for their peaceful serenity.
Definition of "zealotry" - fanatical and uncompromising pursuit of religious, political, or other ideals; fanaticism. Nothing serene about that! But if you swapped it out for "serenity," you'd have something that makes more sense.
Concepts you could consider would be concepts based on the shapes and origins of the suit pips themselves, or perhaps what they evolved into when the tarot deck came into being. Spades became swords, hearts became cups, clubs became staves or wands, diamonds became coins (or to some, pentacles). Use that as a starting point and see what your inspiration comes up with.
I could see a few possibilities. Swords could be warriors/knights. Hearts could be Buddhist-esque monks/meditators/serenity. Clubs could be martial artists/fighting monks like the Shaolin, or perhaps even rangers/hikers/protectors of nature (I can see a Queen of Clubs as Mother Nature, easily). Diamonds could be wealth - merchants, perhaps, as royal ancestry didn't automatically mean wealth. You could label them specifically - or you could leave the themes unstated, letting your backers have the pleasure of figuring them out when they see them.
To really solidify the theme concepts, use colors - have the Spades dressed in blue or black, the Hearts dressed in red, the Clubs dressed in green and the Diamonds dressed in white, or maybe purple (a color associated with royalty and wealth). Bit of trivia: purple became associated with royalty because the dyes used to make purple cloth were imported from the Far East and were rather expensive, thus peasants were unlikely to possess purple clothing and royalty were the only ones who could afford them until a strong merchant class developed. I like the idea of opposed colors for the clothing - black spades and white diamonds, red hearts and green clubs. But please keep the pips themselves just red and black - four-color decks are a pain to play solitaire with! In fact, using this color scheme, you could create background art for the spot cards in the chosen colors for the clothes of the courts, in essence making a four-color deck without actually changing the colors of the pips! Best of both worlds! Your background designs can even match the themes chosen for the court clothes - bladed weapons for spades, things associated with love (perhaps cups of wine, the sun, etc.) for hearts, trees/shrubs for clubs and things associated with wealth for diamonds, perhaps coins and other gems in shapes OTHER than diamond, like princess cut, square cut, teardrop cut, etc. If you don't use blue for any of the other suits, when using white for the diamonds you can use a pale blue as a background for white linework.
Lots of possibilities here. Lots of decisions to make - have fun making them!