IGN AU's editor Scott Donaldson penned a relatively short editorial about "near-catastrophic features that have marred otherwise fantastic titles", with Oblivion's level scaling, Mass Effect 2's planet scanning and World of Warcraft's phasing all used as examples. On Oblivion's level scaling (which wasn't tackled in IGN's review of the title):
Even though Bethesda's epic Elder Scrolls IV was released five years ago, it still manages to hold its own as one of the best role playing games of this generation, even against top-notch newcomers like Dragon Age II and Fable III. But between the countless quests, epic scenery, and Patrick Stewart lies a horrible problem: Bethesda's awful level scaling system.
Unlike other RPGs, the NPCs of Tamriel level up alongside the player, so that the same level of difficulty is retained throughout the game. That's the theory, at least. The extent to which you can customise your character in regards to certain skills magical, physical or otherwise is enormous, so unless you build your character in a particular way, you're pretty much screwed by the time you reach the later story quests. Want to spend your first ten levels building a speedy, stealth oriented character with the Thieves' Guild quests? That's great, but your almost non-existent weapon skills are going to make that scaled up Clannfear seem like God on steroids, and that's only the fourth story quest. Spend your time levelling your armour and sword skills however, and you'll breeze through.
Perhaps the system would suit a different series, but the Elder Scrolls? There is no way that its gameplay can possibly stay balanced when the player is faced with such an array of character customisation options. Thankfully, Bethesda has taken this into account, and has designed a much kinder system akin to that of Fallout 3's for November's highly anticipated Skyrim.