With an opposed die system, with both sides using the same die, the probability of one die defeating the other, over time, is 50%. Your very first chart shows this--both sides of 0 are equal.

Let's say you're rolling an opposed d3. Excluding ties, here are the possible results:

wins:

2 1

3 1

3 2

losses:

1 2

1 3

2 3

See? you might as well just have one person flip a coin. You say as much at the bottom of page xci:

if the pools are the same size, your success chance is 50%

My point is, why use dice at all if you want a 50% chance of success?