Using the above means produces a definition by percentage. And while a percentage definition could indeed eventually be parsed out through such means, the question has always been - why? "RPG" is a merchandising category, and so doesn't actually need such things. What's needed is not an exact definition of the term, but a better defined broad definition. And it only needs that because so many different game styles have been haphazardly given the same name. For instance - Diablo, the Infinity Engines, and Dragon Age are by no means the same game style, but they've all been pegged with "Action RPG". And, of course, they all are different from the likes of Temple of Apshai. So, what happens when someone walks into a store and says they "want an RPG". What did they just ask for, specifically? Nobody knows.
If we wanted to actually help in this matter, instead of a using a percentage definition (which would require consulting a pocket computer and backstory whenever inquiring about a new game, and even then doesn't offer any further context for the purposes of purchasing games than the system we have now), rather, what is needed is one of two things. Either dump a bunch of game styles out of the category of RPG, or add more sub-categories to the RPG header category. That way, people can better define what they are looking for. And, well, since so many people shit a brick whenever anyone tries to do the former, it's gonna be the latter.
Unfortunately, nothing will change unless some authority figure introduces such a system, or the merchants adopt something of the sort of their own accord. But for the purposes of exercising the brain, here's the kind of thing it would look like were it to come to pass:
Traditional RPG - a game that attempts to emulate the old-school pen & paper rpg experience on a computer.
* And from there, anything else is - rightly - a hybrid. *
Adventure RPG - a game that mixes interactive storytelling and inventory puzzles (fetch quests) with the traditional rpg experience. Very popular in certain parts of the world.
Storybook RPG - a game that tells a non-interactive story interspersed with periods of the traditional rpg experience. Prime Example: Final Fantasy.
Gauntlet RPG - a game that mixes the traditional rpg experience with run-n-gun combat (as in, running the gauntlet). Prime Example: Diablo.
Action RPG - a game that mixes hack-n-slash personal combat with the traditional rpg experience. Prime Example: Witcherz.
Action Adventure - a game that mixes hack-n-slash personal combat (or shooter combat) with interactive storytelling and inventory puzzles (fetch quests). Prime Example: Mass Effect 2.
Otaku RPG - a game that may make use of traditional rpg elements, but that is primarily designed to give copious amounts of hip in-jokes and in-the-know references to lovers of Japanimation. Prime Example: Undertale.