Thinking about it more, I will say though that it did do something very very right. That is, !SPOILER WARNING! when the main quest tells you to brand the five warchiefs. Usually, the main story in open world games may as well be completely linear. Go to a specific spot and then everything is entirely on rails for the next ten minutes or so. It's almost like it's another completely different game within a game, and for the most part, Shadow of Mordor is the same. But this part, suddenly the main quest is as open and non-linear as the rest of the game. The game gives you a goal, and you can approach it however you want and at whatever pace you want. Brand the existing chiefs directly, brand a bodyguard and have him organise a coup, brand a low level captain and have him fight his way to the top, or clear out the higher ranks yourself and allow him to be promoted just to fill the power vacuum. It's really the first time I've seen any effort put into making the main questline properly fit the rest of the game in terms of design.
I feel like this a pretty huge innovation and represents the solution to open world games that might as well be linear if not for the side fluff that may or may not be a complete waste of your time, and no one noticed (yes, myself very much included).