Paul,
I am still not convinced. The file can be replaced by various rocks available in the wilderness that could shape metal, glass etc.
How much metal is there to cut in the woods?
For a wilderness folder the Farmer is considered by many to be the perfect knife. Whether that is true or not is individual but I still see little use for a hacksaw in a wilderness situation.
I have several SAKs with a hacksaw and I am not very impressed with the saw or the file. I doubt you could saw much metal before the saw teeth are done. Even though the wood saw is little it is an effective saw and will cut wood (wet or dry) till the cows come home.
Bill