Not sure what happened in the show lately to put this back on my radar, but I've been hearing a lot about it this week...all negative, and it's got me thinking about the character again.
I doubt anyone reading this will ever get the chance, but if someone ever tries to make a good one, here's what I love about the character:
Supergirl has all of Supermans powers, but the character is richer in some ways, or at least different. Unlike Superman, she actually remembers her home world. And in my favorite versions of the story, she was older and sent to help him in his childhood, but due to accidents ended up not arriving till he'd already grown up. By itself that's a huge amount of character potential: that the kid she was supposed to protect ended up being her mentor. She has the guilt of not being there for him doubled by having him be there for her, mixed with being a little more balanced than him from actually having both a semi-normal childhood and a mentor to guide her when she got here. However, unlike Kal, she actually knows what they left behind, and in some ways is in a world that is much more alien to her than it ever was for him.
Also Superman, traditionally, is confident and smooth and pretends to be awkward and nerdy to be Clark, while Kara actually is a little awkward and nerdy, and instead of someone with their act together putting on a dorky persona, it's someone dorky who gets to put on an "I've really got my act together" persona. That's a HUGE difference and in some ways much easier for a lot of audience members to identify with.
I think it's a big mistake to view the characters as "Superman is a hero for boys, Supergirl is a hero for girls". They are different, with very different draws. In many ways I feel like I can identify more with Kara...being a bit awkward but occasionally putting on a confident persona to do a job. I honestly never understood the whole "It needs to be a girl for girls to like it and a boy for boys to like it." That's silliness that someone said and too many believed it, but there's never been much evidence for it. Plenty of girls like Superman and plenty of boys have always liked the strong action women we've been given (and contrary to what the producers of several well known movies lately seem to think: strong women in movies are not new, and they have been VERY successful in the past when done right).
Also (and this is something they actually did get right in this and and in the 80s with good casting): Kara is in many ways more likable than Clark.
Anyway...mostly I'm just talking to myself with this, but it was frustrating to see what I thought was a swing and a miss in the 80s and now another swing and a miss with a character that I still think could actually be one of the MOST compelling of the comic book heroes. Instead she's often portrayed as one of the least.
And this is something CW almost always gets wrong with pretty much every show it does: Comic book doesn't have to mean cartoony. And "Kid friendly" doesn't have to mean stupid.