Kara has lost everything. She has lost her mother, her father, her home, her whole planet even. With the irrational guilt of a survivor, she may have “characteristic symptoms including anxiety and depression, social withdrawal, sleep disturbance and nightmares, physical complaints and mood swings with loss of drive” (Survivor guilt). Added to that, she is surrounded by people who look like her but who have no hope of comprehending what she has been through, or indeed what she is going through. Even her cousin cannot understand. Kal may have been born on Krypton, but Earth is and always has been his home. His superpowers are something he grew up with.
Superman is an ideal. Infinitely powerful with unassailable moral strength. What then is Supergirl, infinitely strong but inexperienced, alien and utterly alone? Perhaps she is indeed a rebellious teenage girl whose untrained instincts and enthusiastic excesses need to be controlled by older and wiser DC superheroes.
Perhaps. But is it enough for her to grow up and become one of them? Is it enough for her to be Superman No. 2? Superwoman, perhaps, although Wonder Woman does seem to have stepped into that role.
Kara and Kal may be cousins, but they have lived very different lives. Of course there will be much that they agree on, but for Kara to be a hero in her own right, she must be able to follow paths that no one else can. She must be able to grasp truths and find solutions that no one else can.
Funnily enough, the one person who perhaps could understand her is Doctor Who. Now wouldn’t that make for an interesting cross-over…