Hey, what if she's a great actress? I think it's unfair that people are judging her before even viewing her performance.
And just because she's signed on for six years, it doesn't necessarily mean she'll be on for that long. As Manu put it at SD-1, "The show won't last for another 6 years. It's a contract that ties her to ABC/Touchstone for that long, not to the show. She could easily be killed off by the second half of the season."
And if she was to stay on the show for that long, she could be "out of the triangle" and just another agent because she's a kick-arse actress.
eta: This article does exaggerate her importance though. I agree with Irina Derevko. I don't want anyone taking away Jen's glory. But I doubt anyone can.