And I second the call for small, card-only expansions... With two base sets now, they would be a great addition!
Ooo, more cards. I absolutely love the fact that the base game has a massive volume of Crypt cards. In fact, I tend to have an unnecessary liking for lots, and lots of cards in a game. So thumbs up from me on this.
I commented over in the main Tomb General Forum that I especially liked how the card previews each include a short commentary text piece that adds a little background. I have to admit to a great deal of interest in this expansion.