Although it might be hard to see in the picture on the Banjo Bros website, the panniers are actually not square. The side facing front is cut at a slant to help with heel clearance, which is one of the reasons i went with these. The issue is really with my bike's frame, not the pannier.

I checked out the Civia rack at a nearby bike shop, and when fully adjusted back, it's out of the way of my heels, which would solve 80% of the problem. the only problem is that the panniers aren't totally supported at the back of the frame and could bend into the spokes once they're loaded up, but I have some ideas on how to fix this. That shop is also ordering the Axiom rack, so i'll compare the two once it comes in.

VERY close to a solution here...