well, how exactly would one ~measure~ their success in balancing the open world distractions and the main story? i know some people my mother *cough* that really enjoyed Skyrim's open world, while other people didn't so much. for example, my mother some people would sit in their house in whiterun and eat bread, while others would go and complete *just* the main questline. Others would only play the dark brohood and theives guild questlines and not even bother with the main one. generally the people focused on the main quest had complaints about it's structure. It's really down to what you look for in the game. I personally like story and distractions within the roleplaying capacity, so direction to the main quest will be important to me while I won't mind monster hunting and saving people and occasionally whoring, where as if my mother some other people played tw3 they would probably travel to Oxenfurt and read all the books and that would satisfy them, best open world game, 10/10.
So, as others have said before, it's down to the individual. I think having lots of quests and things to do is wonderful, but I'm also really glad to hear that the quest designers are gods and have a heavy hand in more or less controlling the player. But I also know some people would be put out by an open world game that didn't have a lot of immersion building distractions. I realised just now i made it sound like my mother wouldn't have had played the main quest -- she would have, but she, and other people's parents very much value the little extra things you can do in this sort of vast game.