> With the file and can opener one can rework found metal items like cans.

Have you tried it? I once tried to make little solid fuel stoves out of tin cans, using the file on a Juice XE6. It seemed to me the file was about 3 times as thick as a proper hacksaw, removed 3 times as much metal and was 3 times as much work. Not fun.

I regard scissors as essential for a multi-tool. You can use them to cut tin! Although I still wouldn't want to do it in the field. I'd rather have scissors than a knife blade if I need to, eg, cut clothing off to get to a wound for first aid, and they are often safer or more convenient for every day use. (And to be honest, I think it's nice to have a corkscrew too. It seems silly to go camping and pack a multi-tool and a corkscrew.)

I agree with you about the importance of metal-working, though. I live in an urban environment, so one of my criteria for a PSK is, would it help me escape from a stuck lift (aka "elevator")? According to some estimates, 10% of the deaths in the 9/11 WTC event were people trapped in lifts. A file is also useful for sharpening your knife.

That said, my current commonly-carried tool is the CS4. I like it partly because it is smaller and lighter than the XE6, but the file is one of the things it looses. (The other is the serrated blade, which I can live without). It keeps the woodsaw. I think theoretically the file is more crucial than the woodsaw, but the woodsaw I am more likely to actually use. I have stuck (part of) a hacksaw blade into my PSK. I know I can cut metal with it. I don't know how much practical use it would be.

Incidently, the Juice XE6 has all the tools you mention. Non-locking blades, but that makes it more suitable for EDC in the UK where people can be funny about such things.