As far as receiving backs not being eligible for RBotY, one precedent is that, in S5, then RB Eric Kennedy was in a similar situation where most of his yards came from receiving, not rushing. Therefore, many people did not want to vote him RBotY, which made a lot of sense to me. He ended up winning OPotY, but no position award. This felt like a good solution to me.
This was before the FB fix was implemented, but the idea seems the same to me. RBotY has always been more of a Leading Rusher award.
This was before the FB fix was implemented, but the idea seems the same to me. RBotY has always been more of a Leading Rusher award.