I think it is important not to forget the function of abdominal muscles. I personally think the word “crunch” is describing one of the actions of the rectus abdominis–flexion of the spine. For me it’s like saying that biceps curls are passe’. When one looks at the direction the muscle fibers are running as well as the origin and insertion of the rectus abdominis, it only makes sense to work the muscle in a “crunching fashion” whether one is standing or lying down. That’s not to say one cannot include eccentric and isometric contractions when training that muscle group.
I personally don’t see anything wrong with performing crunches for that is exactly what the rectus abdominis does.