My 2 cents...
All I know is every engine I've taken apart that runs premix always looks a little better than an OMP injected system, especially as more time passes between builds.
Less gunk in the seals and other build-up.
Then of course this might be from premix being used instead of dirty engine oil. Brian's engine which uses the OMP to inject premix looked just like my engines that run premix exclusively. Modern premix is designed to be delivered with fuel through injectors. I just don't get what Rotary Related is worried about.