This is just horribly asinine. I could've sworn this was supposed to be a superhero show. Looks more like Gossip Girl than Supergirl to me. She's literally the stereotypical "awkward but cute" girl that's become the most popular character role in Hollywood the last 2 or 3 years (thanks for that, Zooey Deschanel). If that wasn't bad enough, she lives with a bland hunk that makes "subtle" quips about how he might have a thing for her, and he's just so likable and sweet, despite having no personality at all, that he's the only person she can open up to. People will say "at least she's not just a sex figure" (though one shot in this trailer will dash that argument pretty quickly). She wasn't to begin with, she was an interesting character that provided a nice dichotomy to her cousin, Clark. She wasn't "sexy" until she started making TV appearances and companies couldn't figure out how to market an interesting character.
Also, in the comics, she sought out Superman right away (close to it anyway) and slowly learned to control her powers and accept the idea of being the "masked" (or glassesless) hero. It showed enough of her personality to like and understand her, but it showed actual growth as a person and an ability to adapt and mature when need be. Here she's just like "I want this guy to like me so I'm gonna tell him who I am and the he'll fall in love because that's how love works, right 11 year old girls?" Besides, who wants to write more characters when we've barely written any of the ones we have?
It's literally a terrible teen girl drama where sometimes she punches people and lifts busses. Why did this even have to be a superhero property? Because they're the only things selling better than teen dramas nowadays? Also, you're kidding me, Jimmy Olsen is a hunky black guy so he can be a love interest. Because we just had to throw a love triangle in there, and there aren't many hunky model guys with no personality for main female characters to gawk over in media, so let's make them all that in this show. I don't even like Arrow that much, but at least they've read a comic, and at the very least, he's not a stereotype of every popular show who shoots arrows sometimes to pull in that "nerdy = trendy" crowd. I don't like it, but I'm not surprised in the slightest.