@MasterVG71782
I think time should definitely be heavily weighed in the difficulty rating and should be weighed higher than perhaps KylieDog & Getrdone are counting for. Just because its an easy grind doesn't mean everyone will take the time to do it. I think a game like White Knight Chronicles should be a 4-5 stars based on time alone. 1000 hours, are you kidding me!? If that is true I'd say that's 5 stars no matter how easy the rest of the game is.
Percentage wise I would say a difficulty rating should be broken down to roughly 50% skill based and 50% time based. Of course we are not that scientific with our rating being a league thats meant for fun. But polling from other sites like ps3trophies.org and getting a larger user base of voting I feel that our ratings are accurate. Of course there will always be ratings that people would argue otherwise. Some people might naturally be more skilled or have more experience at certain kinds of games so its easier for them. Some people may have used a guide to find the tough to find collectibles the first time and others had to play the game a 2nd time or spend countless more hours trying to find them all. Some people may have boosted and others didn't. There's just too many factors really.
Edit: meant to write 5 stars for the 1000 hours.