Live action rather than image-based book trailers can certainly work and be effective. This trailer for The Graham Sage by Anna Belfrage is an example where it does work.
The footage of the couple is without dialogue (always wise) and is just out-of-focus enough for us to fill in our own ideas of who these people are. The scenery is evocative and the score is fraught with tension.
The simple captions tell the story well - if maybe including some spoilers - and make us care about what happens to these two.
That's the whole idea of a book trailer, to spark enough of an interest to make us want to read the book(s).
