DR Jennifer, I agree with you about the over-spoilage that is done in promoting shows. One reason der B and I rarely go to the movies for ourselves is that most of the films have been condensed into the single succinct minute in the trailers, after which why bother? The film becomes a peroration of the trailer. (There's that word again!)
The other thing that bothers me about the sneeks, for television, is that they always make everything so important, underscoring each and every event with a doom-laden thud.
Maybe, instead, what the previewers could try is having two or three members of the cast sit down together, and talk about the show a little, in a casual friendly way, without giving away all the details, and invite the viewers to watch the new episode.
Or maybe not. My approach wouldn't be "dramatic" enough.