[This is just my opinion, not meaning to offend anyone or piss anyone off. This is just how I feel.]
There's so much crap on the internet regarding Bella Swan being a terrible, undeveloped, idiotic character. Maybe some of that is true ... I'm not sure. I try not to discuss Stephenie Meyer's writing skills too much because I end up screaming at people but she isn't the best, admit it.
Anyway, I personally love Bella Swan. I am incredibly fed up and aggravated by the idea that women nowadays have to know some kind of immense self-defense or have a super power to be considered a powerful female icon. Power isn't all about physical power.
Bella begins weak, physically and emotionally. Very weak for that matter, this is shown when Edward leaves her. During the period in which he was gone, although still struggling to come to terms with his departure, she becomes a hell of a lot stronger. She shows courage when confronting The Volturi, because let's face it we'd all shit bricks if they came near us, right? She makes a stand when forced to choose between two of the people she loves the most, by refusing to choose either of them. When Edward was about to be killed by Victoria/Riley she acted quickly and diverted them.
Throughout the saga she becomes a hell of a lot stronger. She even stands up to Edward for the life of her child. Some may consider this a ridiculous decision of hers but personally I admire her for it. She saw it as her child, and only her child. Not the monster that everyone was labeling it (she does the same with Edward though). Like a mother does, and should, she only saw the good in it.
I love Bella because I can relate to her, unlike most other females on TV or in movies.
She is often weak. She does make poor choices. She suffers. She gets hurt. She struggles, and overcomes it. She cries. She complains. She's a bitch and gets angry.
This to me is realistic ... because we all do the same at some point in our lives. She isn't perfect, and neither are we.