Au contraire, I just checked the REI website and their video blurb on the ten essentials and it still includes a knife - specifically mentioned as a component of the repair kit. They illustrate one of the new Leatherman models with small pliers and a relatively modest blade. They are not pushing the Jim Bowie, Roman short sword, "survival" knife that is still peddled to the unknowing. I usually have some sort of a knife with me when I am out and about - I have used it too. Over the years, I have carried a Swiss Army Knife the most often and it has been perfectly adequate. I did switch to a Leatherman about five minutes after I first held one - the pliers are great for freeing up jammed locking carabiners.

I very much like the "ten essentials" concept, but you need to think about what you are carrying because you will often vary the components depending upon the circumstances - the Sonoran desert requires more water in your pack than does the Pacific Northwest. When I was working in Canyon de Chelly, I learned never, never ever to enter the canyon without carrying at least 60 feet of 9mm climbing rope, even if no climbing was on the adenda. In that terrain, it made good sense....

If more people had carried the essential ten, they would have had a much more pleasant excursion and maybe even survived.