From Rise of the Runelords:
Exceptional Stats (Ex) Karzoug was destined from birth to become one of the greatest wizards of his age. As a result, his ability scores were generated using 32 points, rather than the standard 35-point elite array. Additionally, he has much more gear than standard for an NPC of his level. These modifications increase his total CR by 1.
The real reason for the character’s stats is probably balance, as writers knew as far back as Dungeon’s print run that solo mages in D&D 3.5 are defensively underpowered for their challenge rating. You can see this in Touch of the Abyss (by Wolfgang Baur, Dungeon #117, December 2004), where a wizard is possessed by a malevolent spirit to raise his ability scores and makes especially optimal use of spells and terrain to survive.
What I like about this statblock though is that it explains the character ability with an in-setting context. It evokes the sense of something in-setting, rather than something mechanical.
A movie character might shoot someone because it’s dramatically appropriate at the end of act two of the main plot, but that’s not how the audience is presented with it. They’re engaged in the story and the motivations of the characters and the conflict, not the nuts and bolts. Even if some film student understands a movie on a mechanical level, as a game designer or dungeon master might in his game, he’s also watching on the level of the fiction that everyone else sees.
What makes Dungeons & Dragons engaging, for me, is the connection to a malleable, coherent, fictional world. If you’re just playing like a miniatures skirmish game, then for me, that’s missing the point. Aramil the dwarf isn’t just a collection of fighter feats, and the places he adventures to aren’t just encounter sets. I think the biggest advantage of tabletop RPGs over video games is how you can go beyond the depiction of graphics and experience a world which, although fictional, is coherent and interactive and interesting all the same.