Hi Eric,
Well said, and good point. I more reacted to Don's statement that hardtail bikes don't benefit from different styles of axles. For many instances, the standard QR is adequate, true enough.
Regarding the OP's specific question, really his second question, which was if there was any benefit of standard 10mm vs 10mm through bolt vs 12 mm step down through axle, here's my thoughts:
On a street/DJ bike like the NS, I'd skip the standard QR personally. The amount of pressure that the QR itself can apply is limited, due to it's tiny cross section (5mm nominal diameter, minor thread diameter even smaller still). It's the pressure that the QR can generate against the sides of the hub/frame interface that hold it in place. Compare that with a 10mm through bolt. The cross sectional area of the through bolt is over 4 times larger than the QR skewer (78mm^2 vs 19mm^2). The step down 12-10mm through axle does not gain any cross sectional area over the 10mm through bolt. If I were looking for the most practical solution for the NS frame, it would be a 135 hub with the 10mm through bolt - max strength, minimum cost.
Furthermore, with the new Hope Pro 2 hubs, I believe it uses the same actual hub axle (17mm dia) for all configurations, so axle strength itself isn't really too much of an issue, though the 12-10 step down theoretically would protect the axle from compressing/buckling in the center, and failing through such a catostrophic event.