What is wrong with the following sentence (from a New York Times article by Manohla Dargis)?

Still, it proved that a studio division could make money, win awards, attract talent and excite the audience, which is why Miramax and all it helped wrought is one of the best things to happen to Hollywood since the end of the old studio system.

Or am I, like Jennifer Garner trying to tell Conan O'Brien that snuck is not a word, stumbling over some once-bad English that quietly gained acceptance while grammarians' heads were turned?