The problem I have with her character is that she is so unimportant to the plot. Take her away and script works fine. Being so unfunny only makes her worst.
This is true as well, she serves no real purpose in the story.
Unless of course for those people that think it was somehow important that Darcy shot Thor with a taser and made him yell out funny sounds...
One of the things that bothered me about Thor was the silly humor. In Iron Man, it was mostly Tony making jokes, but with Thor they spent too much time trying to be funny at his expense like with the taser and getting run over by the car thing.
The movie also REALLY should have started with Odin's narration about the shared history of Asgard and Earth. You start with your strongest material, NOT with Darcy complaining in a van and asking to turn on the radio.