Anyway, I'm going to talk about quests now. Quests have come to be an assumed part of just about every western RPG. JRPGs are, on the whole, more linear than western RPGs, and thus can control the flow of story and gameplay more easily, providing the player with regular feedback on their actions, but in a nonlinear (or at least less linear) RPG there is an ever-present risk of the player’s actions feeling meaningless (I’m looking at you, Legend of Mana). Quests are a way to avoid this – by placing quest-givers around the world who need the character to help them with some problem, the player can find regular short-term goals to guide gameplay as they slowly progress toward a real or imaginary goal.
There are, however, a couple problems with quest-based gameplay (actually, more than a couple, but I'm going to try really hard to limit myself to two). One is that it severely limits the range of possibilities for the story, because engaging in endless quests only makes sense if your character is an "adventurer" - which really just means that they're the kind of character that likes to go on quests. Another problem, which is closely related to the first, is that it prevents your character from having a very strong personality, because their actions are largely dictated by what various NPCs tell them to do, and because you're rewarded for playing the kind of character that will do any and every quest (that isn't eeeevil) regardless of how silly or out-of-character it is. Put another way, it forces you to play a character for whom no task is out-of-character.
So how do we deal with these problems? Well, I guess you could try to address the second problem by making the character picky and refuse to do certain quests, but that doesn't change the fact that they're an adventurer with no self-determination, it just means that there's a more limited range of tasks they can do. You could try to fix the first problem by writing the setting such that "quests" aren't random mercenary assignments but structured actions leading toward a definite goal, but then you've just made a linear game. Linear games can be fun, but right now we're trying to figure out a way to make a less-linear game more interesting.
What I would do is change the nature of quests by making them character-driven. As it is, in many cases quests are just excuses for you to go and loot a dungeon, because you read online that some rare item you want is in there, so why can't going to find that rare item just be the quest? And I'm not talking about going to fetch it for someone else, I mean that your character finds a book that talks about some powerful rare item that's supposed to be hidden at location X, and your character now has the "Find the rare item" quest, because they want that item. This is a very simple example and doesn't sound very exciting, but you can push the idea into interesting places by adding one more layer: character goals.
The quest described above fulfills a pretty clear goal: gain power. We'll say, then, that this quest is under the umbrella of the "gain power" goal. Now what if, in the book, you also found a reference to the person who created the rare item (let's call him "Melchior")? That might spark another goal: learn more about Melchior. Perhaps if you start looking you'll find out that he's still alive (somehow), and you can eventually find him and befriend him. For that matter, your character might be interested in becoming a master blacksmith, in which case finding Melchior and becoming his apprentice is a way of acheiving a very long term goal (maybe you've had the goal since the beginning of the game).
So we have a series of goals, and each goal can be forwarded by a series of quests. You still have quest givers, but rather than being people who ask you to perform a task on their behalf, they're people who provide you with help on the way to completing your goals. Every once in a while you encounter an element new enough that it creates a totally new goal, such as the first time you hear about a potential future rival, the Black Knight, or the first time you meet a potential romantic interest. The people or places where you first acquire new goals are effectively meta-quest givers, which spark a whole new questline. So far, we've managed to make the quests seem more personal, but we've done so just by rewording the same quests you might have been doing anyway (instead of going to a dungeon retrieve item X for NPC Y in exchange for item Z, you learn about item Z from NPC Y and go to the dungeon explicitly to retrieve it).
But we can get more work out of this idea. What if goals aren't just folders that hold different quests in them, but equippable like items? While you have the "gain power" goal equipped, you're more likely to find quests that fall under than objective, and it affects your dialogue options with NPCs. Maybe they even have game mechanical effects (the "get revenge" goal makes you do 5% more damage to enemies, while the "become a master blacksmith" goal grants you +10% xp from repairing items, etc.). What this means is that the player has a mechanism for explicitly telling the game what they're interested in doing (maybe they think the Black Knight sounds interesting and want to find him, or maybe they don't really care), which lets the game give them more content related to the things they're actually interested in pursuing (rather than giving them quests in a totally haphazard manner). In fact, you could use the player's choices of goals to pursue as a way of determining what kind of form the overarching story and their ultimate goal takes.
If the player is pursuing all of the sneaky assassin related goals, then the game will start to focus more on stealth and won't even bother presenting the player with quests that are out-of-character, like the "become a knight of the order of X". If, however, the player pursues the "become a knight of the order of X" goal, the sneaky assassin related goals don't show up, and the player may in fact acquire the "destroy the sneaky assassin guild" goal. If you want to have multiple endings to your game, then you can make several climactic-sounding quests, but which one appears for your character depends on what kind of character you've been playing. The less-curious player might go through the entire game thinking that the quests they played through were how the game was "supposed" to be played, because they aren't presented with options that don't make sense for the character they're playing, while the curious player will discover that different options allows them to effectively play a different game altogether.
Well, whether you like the player-customized gameplay idea or not, I don't see any reason why developers shouldn't start making a habit of making quests about your character, instead of making them about the NPC that gave the quest to you. It seems like it would just be more satisfying to achieve your own goals than it is to help a person you've never met before achieve their goal and get paid 200 gold pieces for it.