This sounds like an interesting idea. I think it would be really easy to have the four suites represent distinct factions and they all have aspects that could be drawn upon to characterise them. 

For example, Pentacles, sometimesd Coins is associated with Health, Wealth and Physical: They could be an order of Mercinaries but they are also associated with Earth and Home, so they could also be a Dwarven like civilisation of Hoarders with strongholds deep in the earth, their suit in more standard playing cards is Diamonds so... mining again and they are associated with the Female, so perhaps a Matriachal society?

Anyway, thats just a quick brainstorm but I think the tarot as a starting point could give people a really strong basis for building characters that have a place within a given faction.

Consider me interested and feel free to get in touch if you would like to brainstorm and flesh something out!