Ardra tries to seduce Picard, suggesting that he act out his inner desires for a member of his own crew, but she takes the form of Troi when doing so. Picard does have unresolved sexual tension with a member of his crew, but it's with Crusher, not Troi. This is foreshadowing that Ardra isn't as all-knowing and powerful as she claims to be. She's just cold-reading Picard and assuming that he has the hots for the chick with the cleavage.
On a meta level, the name of the director who believes that Ardra is who and what she claims to be is named Dr. Clark. As in Arthur C. Clarke, who has been quoted as saying “Any sufficiently advanced technology is indistinguishable from magic,” which is the entire method behind the con!
