Lol, I thought he deserved a card, and as an innocent child I figured the Fool fit best. He's unsophisticated and inexperienced, and with an open heart walks straight into trouble (or the flower garden).
Given the number of godlike beings, the prevalence of mental powers, and the fact that they've clearly stated that thought is the foundation of reality, it wouldn't actually be that inconsistent to have a tarot deck in Star Trek that actually works.