Beautiful but lacks depth.
Oblivion offers much customization. One can make one's own character class, spells, enchanted items, purchase one's own house and join one of several factions. Typical to Bethesda-made RPG"s, the game features a main plot, sub-quests, and the open-ended game play that allows one to adventure at one's leisure. You can be a member of the Thieve's Guild, the Mage's guild and the group of assassins known as the Dark Brotherhood or join the rowdy Fighter's Guild. Players can even rise to the top of a guild through completing enough quests. Yet, quests really fail to have a meaningful effect on the player or the world around them. Becoming the leader of the Mage's Guild, for example, means that the player has a room to stay in, some new robes, and a chest that will duplicate alchemical ingredients. Sadly, being the most prominent magic user in the entire Empire has little more meaning. It does not come to bear when considering your standing amongst other factions. One would think that announcing oneself as the archmage at a fine inn would merit a discount or some extra show of respect. True, the archmage (or leader of any of the other 3 guilds) can have a lower level crony follow him around to help in combat which is better than nothing. The result is that there really little incentive to actually become the Archmage or leader in any other guild. In fact, in the Dark Brotherhoood a mid-level quest results in perhaps the coolest reward in a guild quest: the receipt of a beautiful, black horse named Shadowmere. The impact here is that you will likely use this horse for the rest of your playing experience, which ends up being more meaningful to the game play than rising to the top of the guild itself.
The magic system leaves much to be desired in Oblivion. While it is compelling that higher ranking members of the Arcane University can create their own spells, it simply that one can create a spell based upon the same simple spell concepts already available, just to the player's specifications. Its much simpler to simply go out and find a guild mage who is selling a spell approximating what you want. This is particularly so given how troublesome it is to custom make spells in terms of the required component. While magic can be an effective way to go combat-wise, magic ends up being aesthetically boring in the game. A little flair of fire here, a cloud of cold there and this ends up being true even for the most powerful spells in the game. A high level fire spell, for example, should have a lot more to it than a little flair of fire that simply does a lot of damage. The game designers could have stood to limit customization and variety in favor of some more compelling artistry in the magic system. These sorts of cinematic details are important to any RPG
The same goes for the character building concept. In the system (which is based upon the Rolemaster paper and pencil game) players can choose pre-made classes that are compilations of 7 class skills. While this level of freedom is indeed exciting, Bethesda failed to make many of the skills relevant in terms of their usefulness in game. For example, the security (lockpicking) skill in the game is pointless to take because it is very easy to master the optional lockpicking mini game. You could be a clumsy Orc fighter with a virtually no lockpicking skill and still be able to pick the hardest lock with relative ease. Moreover, one of the most exciting class abilities, Alchemy, is also poorly developed. Players can make poisons, healing potions that have more classical "magic potion" effects such as breathing under water and invisibility. Yet, the game fails to give you any obvious recipes. The result is that the player simply collects random ingredients and tries random combinatiosn to create endless random potions. How exciting would it be to find a recipe for making invisibility potions and then to need to research where to find ingredients only to then adventure out to collect them? That would make for a great incentive to take the skill. Poisons, too, fail to be very meaningful. Poisons could render someone totally poisoned, inflict some awful disease, cause violent spasms, or simply kill a certain type of creature outright. Instead poisons simply add some damage to a weapon, whether that damage effects health, mana, or a character statistic. While these can certainly be useful and are a good start, they are ultimately dissatisfying. The poison system is thus too bogged down it what poison does how much damage to what statistic. It statistical damange were to be the focus, a far better idea would to have a poison, that say, clouds the mind of enemies such that they cannot cast spells for a short period of time. Perhaps a poison makes it so that an enemy is dramatically weakened for a short period. This would make poisons actually worth bothering with.
Athletics and acrobatics are also quite pointless to take as class skills. In Oblivion, using a skill in game is the primary way to increase the stat. As you spend a great deal of the game walking (running) around and jumping from here to there, your character's skill in these areas will improve.
Also disappointing is the game's treatment of the persuade and mercantile abilities. Players who want to design a character with strong social abilities are simply out of luck. The persuasion skill requires the playing of a persuasion mini game. The mini game is a spatial puzzle the solving of which can take minutes to get a single character to like you. This is the only impact the persuasion skill can have: making people like you better. You get no special dialogue options of any kind. Its far easier to simply bribe someone to increase your reputation on the rare occasion that you might have use for persuasion. Moreover, it does not take long for money to be of no consequence in the game. Mercantile allows you haggle for lower prices on bought items and higher prices on sold items. Even simply buying or selling things can increase your mercantile ability. Unfortunately it takes so much to level your mercantile skill that it is hardly worth bothering, particularly at the point at which money becomes a non-issue fairly soon into the game.
The game could stand to pay more respect to Divinely oriented characters. There is no faction for Priests despite the detailed Pantheon included in Oblivion. Indeed, healers are merely normal spellcasters who have taken the "Restoration" school of magic. At the very least, the game could have included a more meaningful divine system that includes the potential for losing favor with one's patron God or Gods.
Loot, money and treasure are all level-based in the game. This means that no matter how many wealthy nobles a player manages to pick pocket or how many palaces one spends hours burglarizing, a 1st level character will receive very little money. This means that it is never really exciting to delve into deep dungeons or pilfer high-risk mansions. After all, you are only going to find something that is around your level in terms of value and strength. A player specializing in thievery should be able to make money quickly given the risk they are taking. The game is very sensitive to thievery and murder and guards do not hesitate to come after you, take all of your stolen goods (which they somehow know to be stolen) and imprison you. More powerful items lose their impact at higher levels because every highway robber you encounter is using a glass weapon and wearing Mithril armor.
To add to the sense of superficiality in the game, voice acting is lackluster at best. There are only a handful of different actors used. These actors don't even bother to create character voices to add variety, flavor, and personality to the NPC's one encounters. While this may seem like a petty detail for a video game, it is not at all petty for a roleplaying game whose emphasis is on immersion, ambiance, and story. There are only a few isolated exceptions to this blandness in the characters one meets which is really unfortunate.
At the end of the day, Oblivion is a beautiful game with great potential. It is a definite must for fantasy RPG fans. However, the initially overwhelming breadth fails to deliver the needed depth to make a truly excellent RPG. It as though one becomes so excited about the many possibilities in the game only to be disappointed by the superficiality of most of them. This is particularly true given that it would be a huge task to explore all possibilities of character design, quests, and other such things in the game. A better a approach might be to substitute some of the that overwhelming breadth for more meaningful impact and thoughtful development. Either way, Oblivion is a lovely game that will be sure to bring loads of fun to most gamers.