In order to avoid confusion and possibly just waste your time, RPG must be defined in this context lest you take your own conception of what an RPG is and therefore have the whole article be meaningless.
In my mind, an RPG shouldnít need an example. Itís a role-playing-game. Therefore, as long as you play the role of something, you are playing an RPG. So how is a role defined? If we arenít careful, just about every game ever to hit the face of the planet could be determined to be an RPG. Therefore we must define a role carefully and tactifully. Merriam-Webster online dictionary defines a role to be "(1) : a character assigned or assumed". Ok, but whatís a character? From the same source: "the complex of mental and ethical traits marking and often individualizing a person". The key word here is "individual". While in a game such as Doom 3 you assume control over a person, in fact you are just taking over the position of a soldier. It could be any soldier, that particular soldier means nothing. Therefore while you are playing a particular type of person, you arenít playing a specific person. This narrowing removes most FPSís, just about every simulation, every RTS, along with a lot of other games.
Hold on, didnít I just say that Quake 4 isnít an RPG because its an FPS? The keyword was most. Nothing in the definition of an FPS negates it being an RPG. And in Quake 4, you do assume the role of an individual. Despite the fact it's an FPS, the main character, whose role you assume, its very defined and could not just be swapped out with any other soldier. Therefore you definitely assume the role of a soldier, named Matthew Kane.
With Quake 4 clearly established as an RPG, we now have to set some terms down for a good RPG. The first category can be directly derived from the definition of character, which we have already found out to be a big part of an RPG. "mental and ethical traits marking and often individualizing a person." Where Oblivion lets you define or not define these, Quake 4 forces you to assume them in the taking of the character. Kane is a kickass marine who gets the job one without an ounce of guilt for the victims he slaughters. He is also the sole surviving marine of an earlier attack and his survival promotes him to heroic status and really individualizes him.
In Oblivion, while you can say whatever you want about the character, the only things the games takes into consideration is a set of stats and following actions that you have performed, so that you can never achieve the status of an individual, just get closer and closer to it. You can have performed multiple quests, be hunted by the footsoldiers, be a level eighteen theif, and hiding in the top tower, but you are still lacking those final quircks that make you a character. Like I said earlier, you could indeed say you are this and do this because you are so and so, but the game takes no recognition of this.
Therefore in this category, Quake 4 wins out. While there might be less of a choice of what character you can play, that character is way more in depth and individualized than what you can achieve in Oblivion.
The next category will be lifted from books. In just about every book that has ever been published, the main character is not only the most individualized, they are also the most dynamic. While itís OK for the supporting characters to be unchanging throughout the course of the story, if the main character does it the book is usually uninteresting and a flop. Therefore the second category defining a good RPG relates to the "dynamic-ness" of the character.
In Quake 4, the main character undergoes not only undergoes life changing experiences such as huge battles and loses good friends, but undergoes a huge physical change when he is turned into a Strogg. This huge change and the change reflected in the character by his supporting cast make Kane into a dynamic character.
Oblivion on the other hand provides only a few oppurtunies for a dynamic character. You can choose to become the Grand Champion, to save the world, or to do several other things. But these really only change the peopleís opinion of you rather than showing a change in the character. And even this is pretty weak as most people remained unchanged regarding you even after you save the world. Therefore the only thing that Oblivion provides in way of character development is stats that increase over time.
Once again Quake 4 provides a much stronger example of a good RPG than Oblivion. While Oblivion gives you a multitude of options, they are all shallow and offer no real chance for character development, on the other hand, Quake 4 gives you a deep and thoughtful path through character development that ends with a definitely changed character afterwords.
The third category is taken from books and games, but mostly common sense. For a character to be an individual and to be dynamic, his world must act and respond accordingly. Itís the world that can truly make or break the character. Since RPGs depend so heavily on characters, it can thus be said that they equally rely on their worlds.
Quake 4 paints a highly detailed universe where humans are struggling and trying to do their best not to be exterminated and consumed by the Strogg. In every corner of the game this is evident. From the beginning cut-scene with a dead soldier floating in space and the crash land that starts you off on Stroggos, Kane is constantly bombarded with images of death, war, and destruction. Being a soldier, these highly amplify his traits. As Kane progresses, so does his world. From simply being another soldier in the fray, Kane evolves into a primary character who has to face great challenges and trials and ultimately affect the world in a huge way, eventually changing the tide of the war in favor of the humans. This huge change, demonstrated in a small way by the ending video showing the relaxing soldiers, and all the preceding little details make Quake 4ís world definitely worthy of a good RPG title.
Oblivion starts off a little more promising in this regard. In fact the first ten minutes of Oblivion make one think Quauke 4 stands no chance. Here is a world in which characters talk to each other and live according to their own little personal rules. Towns, forests, dungeons, and hundreds of people make Oblivionís world that much better. It is only time that hints at and ultimately exposes the true fault in the world. It is very static. Someone playing the game can save the world, kill off half the worldís people, and steal just about every artifact in the game, and any given conversation with a survivor might sound EXACTLY the same as it did in the beginning of the game. Very few people react to the saving of the world (which is actually handled by someone else!), and those that do simply say a sentence or two that isnít even that convincing. This stubbornly static world therefore loses all of the points it gains in magnitude for lack of depth and change.
Therefore ultimately, Quake 4 provides the player a much better world in which the main character can be individualized. Oblivion gives promise of something much greater, but it never comes through on that promise, and remains so stubbornly static that it gives the player almost nothing in dynamicness.
While both Quake 4 and Oblivion are indeed very fun games to play, that is irrelevant in the scope of this rant. A simple rereading of the final paragraph of each category tells you all you need to know about which is a better RPG. While it may only offer one path for your character, Quake 4 provies a much more individualized and dynamic character who exists in a very dynamic world that keeps up with him. Oblivion provides only ankle-deep characterization, superficial change, and a stubbornly stagnant world.[Quake 4, Doom 3, and The Elder Scrolls 4 are property of Raven Software, id Software, and Bethesda Game Studios, respectively. The discussed material belongs exclusively to them and my statements are in no way endorsed by any of these companies.]