Why not try different paths. I restarted my game several times before I finished, when I realised I had missed loads of stuff. I have tried to avoid spoilers by mentioning things only in the most general sense; enough for you to understand, since you finished the game, but not enough to spoil things for those on their first run.
I'm sure you did not complete every quest, in fact, because of how things shift depending on the decisions you make, its probably impossible to complete everything.
The first time I played, I found a skull (quest object) I had no idea where it fitted, came to a completely wrong conclusion in another quest, and missed a number of quests altogether. I took a boy to one woman, then after the re-start took him to another. I backed one side in the war, re-started, backed the other side, realised what b***** they were, but will probably still carry on backing them to the end.
There is certainly enough depth in the world to support several playthroughs, and it looks far too beautiful to shelve quickly.