Hi Nic, Here's my $0.02 of opinion on the design and filework in general. This is just my opinion and of course YMMV.
On the design in general:
1. Overall, I like the design
A LOT!!! 
2. I find that a very nice blade size and shape. It looks good for the kind of general rough-housing that a woods blade will sooner or later receive. It's also small enough to be worn on a belt without whacking your leg too badly, especially if worn in a medium- to high-ride sheath. I'm assuming the blade will have a flat-ground or convex-ground primary bevel (not hollow ground) for robustness of the blade.
2. The narrowing dimension of the flat running along the spine of the blade is a nice aesthetic touch and makes the blade look light and lively, whereas a fixed-dimension flats (as on most commercial saber-ground blades) tend to make the blade look heavier and stodgier.
3. I like the shape and drop angle of the handle. If it is made of canvas micarta that is left rough or beadblasted and if its shape has a significant swelling at the front (quasi-guard for thrusting & hard poking), at the center (filling the hollow of the palm to spread out contact pressure between hand and handle), and at the back (for anchoring the knife if used for chopping or other vigorous swinging cuts), so much the better.
Two things that would make the handle even better IMHO would be:
1) Deepening the finger index groove to help prevent the hand sliding forward onto the blade if/when the handle is greasy. This is definitely just a personal preference on my part, one of those subjective "in the eye of the beholder" items.
2) Not curving the upward line of the scales back from the front of the finger index groove. This curve makes the design shown flow beautifully in a visual sense from the blade edge back into the handle. However, I would bring the scales straight up from the point where they begin at the bottom of the current curve. Especially if coupled with a forward-flare on the scales, that would give my thumb as wide a platform as possible to push against when bracing the blade for forceful push cuts like pointing stakes, cutting big fat tinder curls for firestarting, etc.
I don't generally care for filework for two reasons:
1. It is made of nooks & crannies that can (eventually will) collect bits of plant gunk, food particles, pine pitch, what-have-you. This makes it tougher to clean the knife after use than if the filework was not there.
2. When filework is done on the spine of a blade, it represents breaks along the outer skin of the blade. A high degree of the resistance to flexing of a closed surface is based on the dimension of the outer surface and its resistance to stretching. That's why we can use tubular frames on cars or use torsion-box benchtops in a shop and still have rigidity without going to solid-stock frame members. Anything that interrupts the planar continuity of a surface skin only makes that skin weaker.
IMHO any filework on a knife (for thumb ramp or blade spine traction) should always be radiused at the bottom to avoid concentrating stress vectors (stress risers) at inside corners. Such concentration of vectors leads to easier cracking and breaking of the steel at those corners. The round curvature of radiused filing/milling redirects the stress vectors around the curve and the vectors can't so easily concentrate enough force into a small enough space to tear or break the metal matrix.
Such radiused traction grooves are especially effective if handle scales are brought up to the same height as the tang or thumb-ramp and the grooves are milled into both the steel and scale material in one continuous cut.
Thanks for the bandwidth, -- Greg --
