I suspect the OEM wheel was laterally flexible, not so much torsionally so. Perhaps one of the draw backs to a minimally spokes wheel that has a lot of dish. Add in the reduction of clearances to fit more cogs and cage rub is more likely. As to the "
unnecessary spacer", seems to me that it is necessary after all
I think you'll find that playing with lacing patterns has less to do with performance then spoke count, amount of dish and spoke tensions. Andy