Stieg Larsson was a a talentless hack who had about as much literary style as Dan Brown. The only reason his work is better reviewed is because of the feminist fantasy that is Lisbeth Salander.
A hack is, by definition, someone who writes without a thought in his head about quality or style, only the making of money. Larsson completed all three books for love, never believing that they'd ever see print. GWTDT certainly shares some flaws in common with many first novels and is said to have benefitted greatly from editorial assistance. The second, reportedly, was still being edited when SL died. The third, appareently, was published as he wrote it. For my money, he was definitely growing as he goed. Even so, no, he was no great stylist. But he writes in the plain style quite well and he did succeed in creating one awesome female character and an interesting enough male lead, plus story lines that kept me at any rate tearing through the pages. And in commercial fiction, it's the story after all. Alexander Dumas was the world's greatest, or worst, hack--but The Count of Monte Cristo still holds readers in its thrall...though it takes hundreds of pages for the good Count to appear.
Anyway, for a commercial writer who really could blend terrific style and story, I don't think anyone so far's touched the hem of Lawrence Sanders' mantle.
P.s.: Anybody out there read GONE WITH THE WIND for its style? Or any Sherlock Holmes tale?