"Elastigirl, you see, has adapted perfectly to her role as housewife and mother. As the film begins, we hear her say, "Settle down? No way! Leave the saving of the world to the men? I don't think so." But then she is tamed by marriage. She even becomes "Mrs. Incredible", not only in the advertisements (because of rights issues with Elasti-Girl), but also for the film proper - it's the Incredibles, after all, not the Elastics."
For most of the movie, Helen is portrayed as a typical mother who stays at home to take care of the family. When she realizes her husband Bob has been using his powers secretly, Helen's whole world falls apart and she starts to sob uncontrollably at Edna's. It is Edna who has to tell Helen to pull herself together and remember that she is Elastigirl (http://www.youtube.com/watch?v=eLDWhn8HZfY&feature=related). Only after this instance does Helen seem to finally show signs of her previous fierceness as Elastigirl, boldly saving the world and actively fighting for herself, and now her family as well.
The physical differences between Elastigirl and Mrs. Incredible is also notable, for Mrs. Incredible is portrayed with a more typical "mom" hair along with a wider figure. The article notes that Mr. Incredible changes drastically physically, while Mrs. Incredible doesn't- showing that it's more acceptable for men to lose their shapes but not women. I wouldn't go as far as to say Mrs. Incredible is sexualized, but she is definitely portrayed in a better light physically than Mr. Incredible.
The overall portrayal of Helen Parr seems to be that of a selfless mom willingly to sacrifice all for her family. Despite the article's argument, I personally think that overall Helen was a relatively strong female character who learned to balance her individual identity with her family role. It's true that Helen's name and identity as Mrs. Incredible will forever put her on the sideline, but she definitely showed that she had the same spunk Elastigirl once had by the end of the movie with her quick reasoning and innovative skills. Helen came to save both her husband and her family with her powers, and proved that even a mother can still be an awesome superheroine.