 New York Post's Robert Rorke reviewed the numerous characters with heavy romantic development, noting perpetual "merry-go-round of hookups, breakups and makeup sex", while describing the lack of sentimental involvement of Katherine Heigl's character in the first half of the season. However, he deemed Izzie Stevens "the hear and soul" of the "sex-filled series", due to the season mostly focusing on the events that come to define her as a person. Rorke named her the show's heroine, and wrote that "Izzie is a welcome, calming presence, despite the devastation she experienced when she failed to save her patient and fiancé Denny Duquette", considering her to have been more prominent than the title character, Meredith Grey, whose storyline received negative critiques: "She used to be the queen of the romantic dilemmas. But lately, she's been a little dopey, with that endless McDreamy soliloquies." He also noted Meredith's decreasing importance in the ongoing arc, describing how Sandra Oh's character development was vital to the success of the season, as he compared her "cutthroat exterior" with the emotional side of her personality that evolves throughout the season. New York Post compared Izzie, who is described as having achieved a depth, to Miranda Bailey, noting the maturity they have, which is uncharacteristic to the fellow interns. Robert Rorke positively reviewed Chandra Wilson's performance by stating that she was "formidable".
