I think we'll have to improve on the best working folders out there already. That means keeping in mind the best that the Sebenza et.al. have to offer.
First, a quick clarification. We're designing a "working folder". That means utility folder first, defensive knife second (but still, keep defensive capabilities).
Blade:
The overall blade shape is pretty well-known. We need a generous belly for slicing, and a point that's the perfect compromise between needle-sharp and thick-but-robust. Tip-wise, I think the Krait, Sebenza, and Spyderco Goddard's tip shapes are all in the ballpark. The AFCK's tip is a bit too sharp. Overall blade shape would be a straight-clipped blade with a belly -- like the Sebenza, or the Goddard, or Mad Dog's Lab Rats.
I like the performance of recurved blades, but they're too hard to sharpen in the field. No recurve, but we'll join the blade and handle at a slight angle (aka "forward rake", aka "positive included angle") to increase slicing and slashing power.
The Sebenza has proven that a thin edge, for performance, really works for people. Justifications for thick sabre grinds don't cut it on the purfect folder. That means a high hollow grind, or full flat grind.
Steel should hold an edge first and foremost, but not be *too* brittle. BG-42 is the best of the proven stainless steels. 420V might be an option after it's a bit more proven. Any number of non-stainless steels would work. O-1, A-2, M-2, L-6 (!!)
Thumb ramp on top for control and pressure.
Handle: The most comfortable handles all seem to have slight palm swells, with indentations to lock in the pinky and index finger (the Krait is the notable exception, I can't figure out why it's so comfy!). A *small* dropped guard of some sort up front is nice, too.
Handle material I'm fairly agnostic about. I love G-10 with titanium liners, but I know some people are sick of it.
Opening Mechanism: A hole if you can figure out how to work it into the design without being too unsightly. A thumb disk otherwise. Absolutely no thumb stud.
Lock: NO LINER LOCKS! Again, the Sebenza has shown us that an absolutely reliable, incredibly strong lock is a must. Integral lock, axis lock, some other proprietary lock that is strong and can be manipulated with one hand are all okay. Liner lock bad.
In conclusion:
My perfect utility folder is not that far off from a 4"-bladed, folding version of Mad Dog's Lab Rat, now that I read it. Add a thumb disk, thumb ramp, and a capable lock, and you're there. Offer a version in BG-42 and another in O-1, A-2, M-2, or other non-stainless steel.
Joe
jat@cup.hp.com