"I mean, where's the journey in twilight? She doesn't go on any journey or learn anything about herself. She doesn't really change as a person in anyway. The whole point of the hero's journey is to go on some kind of journey that pushes your limits and makes you discover that you are more capable than you thought. Does that happen in twilight?"

I mean, most of the action if you can call it that, happens towards the end of the books. Bella has to sacrifice herself in order to rescue her mother who she is tricked into thinking the bad vampires have. She apparently has tasty blood.

She has a bland character because she doesn't really have hobbies or interests beyond looking after her parents and her love interests. She also rants about them... a lot. She just lets people walk all over her, she goes along with things her new 'friends' suggest. They like her because she is the new mysterious girl from outside.

I think her arc, if we're being generous, is that she learns about the world of vampires, falls in love with one of them and that she was destined to become one. But also that it is dangerous for a human to be around vampires since she is always getting into trouble because blood tasty.