Honestly, I never loved this much doing quests in any game until TOW. Not only because I love the universe and the critics behind jokes and satire, but because, unlike most Rpgs I've played these past years, you can do quests in various ways that will impact the story and evolution of your character and companions and the places you visit.
I mean, take Witcher series, which was my most favorite number 1. Someone hires you to kill a monster, okay. You go and track it down, and maybe 3-5 times, in the 3 games, you can chose to spare the monster you've been paid to kill. Most of times, the only thing you can do is follow the quest, kill, and ask more money for reward.
Pick almost any quest from TOW, and you'll find different ways to complete it. You can even never complete it by finding a better bidder for doing the task.
No matter which quest you get, you can do it in various ways during combat, during dialogues and decide to screw everybody in the end and go for another side in the end.
Also, you can make a faction believe you work with them and think the same way they do, then screw them in the long term.
I've never seen this field of possibilities in any other 3D Rpg game so far.
Quests may not be the most original, but nowadays that is pretty difficult to invent new quests that we'd never have seen anywhere else.
W3 earned its medals for the universe, for the have-sex-with-each-girl-you-meet-if-you-want feature, and the overall writing way above what we usually find in usual rpgs, along with a dark and uncensored view on heroic fantasy, impressive graphic engine mixing poetry and beauty of fairy tales with humans inner darkness and talking about real world mature subjects behind all of it.
TOW has great writing, with ton of humor at different levels, and give you the opportunity to chose how you will do a quest from start to end, also letting you chose to fail it for a more suitable outcome in your opinion, all this in a world filled with clues, secret paths, and little fun or less fun stories to read and learn, sometimes very useful for some quests, sometimes just to make you laugh.
They've invented everything, and made very fun characters and companions which make the game immersive and give it this special taste you don't find at each corner, with all qualities w3 has, except for the density, the scope, and all the boring stuff all over the map.
They don't reinvent how a wheel will roll, but they make it roll in various ways that gives it pepper and sugar all together.