If this trend holds through future patches, ARC got hosed. PIE is an extremely undesirable primary damage stat for a DoW; STR or DEX is a much more beneficial option, due to being able to double-dip with the added attack or accuracy. And with the Strength In Numbers bonus making accuracy concerns irrelevant anyway, this means that non-ARC DDs can pound STR/ATK and always get a return on investment, while ARC is essentially forced to screw around with otherwise-useless PIE.