Kelly Thompson's incorrect use of the term "imagination," examined here, leads me to another line of thought: is "not showing" a given phenomenon inherently put more demands on the audience's imagination than "showing?"
Over the years I've seen innumerable comments in the affirmative. Here's a book-length study addressing, at least in part, the role of radio serials in promoting the imagination of their audience, since those who listened to radio programs had to conjure up the physical appearance of the perils faced by the Shadow, or the comic appearances of Lum and Abner.
With the horror-genre in movies, some critics have a particular preference for "indirect horror," even though the cinema is inherently a visual medium. The 1942 CAT PEOPLE frequently receives praise for not showing "the monster," and allowing the audience to make up its own mind as to whether there was a "cat monster" at all.
The absence of a "boogieman" figure, however, does not automatically mean that a given work is more "imaginative" than one that has such a figure. CAT PEOPLE, though it has its virtues, is not especially complex beyond its basic "is-she-or-isn't-she-a-cat-monster" schtick.
For example, though the 1941 WOLF MAN flirts with a similar "wolf-or-not-wolf" plot, for whatever reason the film does commit itself, making clear that Larry Talbot does indeed transform.
Despite discarding this particular ambivalence, however, I find WOLF MAN to be far more imaginative, far more symbolically complex than anything in the repertoire of CAT PEOPLE's producer, the somewhat overrated, Val Lewton.
However, at this time I don't choose to provide a proof of this opinion, since it is merely a "quick thought." I don't imagine that any regular reader of this blog would doubt my ability to produce such a proof, though.