I think the issue is that she's trying to do something different with this film. There always are a fair number of people who will tend to want an artist to do what they fell in love with her for doing. For a lot of people, that was "I'm the One that I Want," which is understandable--that film is a masterpiece. The problem is, she can't just do the same thing over and over for decades. She has to move on and develop as an artist.
Furthermore, in addition to being a brilliant comedian, Cho is a dedicated social activist, and she is furious about the political situation as it's been developing during the past decade. As some posters here have noted, she's not alone among comedians--and, in fact, a few of you have accused her of doing "imitative" or "derivative" work, but I don't think that's a fair assessment. There are, plain and simple, an awful lot of outraged people in this country who do not at all like the way the Bush Administration has been running things. Comedians/satirists have the time-honored role of giving voice to those kinds of feelings, revealing hypocrisy, and speaking truth to power. And, in fact, that's what a fair number of them--including Cho--are doing.
I think it's probably fair to say that some of her later work has been less "stand-up" in the traditional sense than righteously angry, take-no-prisoners political commentary by an incredibly talented and funny woman. It's not fair, though, to accuse anyone who is as outstandingly talented and disciplined a writer as Cho of "rambling." Her shows are, in fact, beautifully structured. And I don't agree that her later work is, therefore, inferior to her earlier work. It's just a different kind of performance.