I have seen Mario 64 defined as an RPG. YouTube sure does in searches.This thread just shows that we really need new names for the video game genres.
Someone already stated it, to me the key is it should be a character you make, not one you are given to play. Do you make character yourself or are you given a role? If you make it yourself, its an rpg. Anything else is something else. Fallout 3 might fit that category but F4 didn't.
I generally play a dying breed of RPG, the ARPG, And those are all about making all the choices yourself. I don't play story driven games, too much dialogue, not enough action.