Faded burlap (canvas micarta and wood for that matter) is a simple oil and buff during routine maintenance.
The small pinholes remaining in some of the finished product is probably more of what you are referring to. I agree somewhat. I have received new knives that made me wonder if the material could either be produced better or if finishing of the material can be done better to remove/fill the pits, air pockets or whatever they are.
Having been through and still own several handfuls of burlap handled knives, the majority of the burlap I have received has been tolerable for me in my uses and desired handle aesthetics. I've seen newly finished wood handles with canyon like checking that would swallow the typical void or three on a burlap slab.
Life here on a Northeastern coastal boundary, the burlap knives have worked well for me with no movement issues. Only a tactile texture change (the exposed fibers to the elements and regular oiling) that, IMO, is for the better and improves the grippy feel.