This wilderness trinity is a tough one. I've also struggled with it.
What was taken would have to depend on the situation.
Where I was going, how long I was going to be gone for, the type or terrain, etc....

For myself personally, I have expanded to include an essential 4 instead of 3.

In my very limited experience, I would have to say that I would take
1) Folding Buck Saw or Folding Swede Saw
2) Chopper of some sort (chopper knife, hatchet, machete, etc)
3) Smaller knife
4) Multitool of some sort.

For the area that I live in, I would take
1) Folding Swede Saw
2) Scrapper 6 (or SOD when it gets here)
3) Koster Bushcraft
4) My Leatherman Charge

Of course, this is all subject to the situation that I would be going out in.

Cheers