I didn't vote on a number.
I think it said somewhere that alot of quests are hand written,which probably means deeper quests etc.
Radiant story ( i believe ) may play a part in how many quests we have,depending on a few things.
1: How popular/un-popular you are.
2: Your playstyle.
3: What locations you visit
4: actually,not sure on more ways yet,but my point is,you may never get to do all or most quests in one playthrough,because of radiant story.
Thats the way i see it anyway.....and if that is the way,i would prefer it