I think quest arrows completely destroy the experience. They remind me of MMO's which are meant to be sped through without any knowledge of what you're even doing, basically pure grinding or power gaming. But that's not Elder Scrolls. Elder Scrolls actually has interesting quests that are worthwhile, and I think it adds to the experience when you actually have to find stuff with given directions, and not just follow the little green arrow. I'll admit, Oblivion did sometimes have stuff like this, directions to a place so it made it easier when we could use mods to turn off quest markers, but not all the time did we get directions, actually it was just very few times.
The main problem that is brought up tends to be NPC AI. Since NPC's are out doing many things every day, and sometimes different things on different days it can make it very hard to find specific NPC's. I've often thought that a solution to this would be to have it so you could ask other NPC's about quest specific NPC's and have them tell you their schedule, or what they might know about their schedule. This might be something too complicated, but only because all lines will be voice acted so they can't just mock up something that reads the AI packages and converts it to a reply. So there you go another thing that full voice acting ruins (though I'm not necessarily saying I'd rather not have voice acting).
Hopefully what people saying about the game having no HUD at all is true, and what we write in our journal, and conversations we have with other people actually help us get to where we need to go rather than the magic green arrow that knows all.