I'm not really a stickler for realism or details (I understand you can shoot while carrying items) but this is just a stupid idea thats only purpose is to support your laziness.
Also it's not really an easy fix anyway since whenever you rightclick while holding something you go to set it down.
I am all for using the harvest button on forageables. Would go great with picking up the herbs with a boat over my head too then. Annoying as fuck, so why not make it a bit more convenient?