You're probably right about his intent. I'd probably say that CPM M4 would likely further outperform D2 when each is at its optimum HT and geometry as well because of the thinner section allowed by the M4.
Based on the hardness and HT of the Benchmades I'm using, neither the D2 or CPM M4 is likely at full potential due to production and cost limitations, though I fully enjoy both. I'd estimate the D2 is closer to its potential, but I'm sure as with anything production vs. custom there would be room for improvement.