How much have you played?
I'm 48 hours in and I haven't even finished the big fours quest, hardly done the main quest, and have only done one daedric quest.
What do you consider the big four quests?
I have done the main, college of winterhol, imperial army. And now im working on the companions. I consider all of those big questlines, but i also consider the dark brotherhood and theives guild to be big which would be 6.
the quests arent that long though i wanted to do more in the main quest but it was still good, also the mages guild you could probably finish in about 3 hours..