I never was a fan of Elena, but that isn't because 'it was all about her' and more about just not liking her character and the way she was written.
I agree though that the premise of the show was always about how Elena, being this human girl, was suddenly thrust into this dangerous supernatural community and how she dealt and survived. When Nina left they tried to rebrand as it being about the 2 brothers learning to become a family again and I would have been able to buy that had there been more leading up to it and not just them fighting over a girl until they just weren't
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