I disagree with the OP in several aspects regarding Hazel and mainly about her motives, rose coloured specs no less.
She did mess up big time in the beginning, she was slutty as someone else said.
Why has she changed? Because there are no men she fancies anymore, she has said she is bored because of it and dislikes all her housemates.
She hasn't changed out of some reawakening goodness, she has awoke because she has been booed every week since Daley left, needs to amend the way she presents herself and I bet the moment a fanciable bloke would have walked in, we would get a repeat of it all again because she doesn't care who, anyone halfway decent would be fair game for them to have sex on TV and to further her career in lads mags.
So sorry, Saint Hazel doesn't do it for me, if she hadn't been like it in the first place, she just might have got through, face it, she is only there because of twists and Callums dire behaviour, nothing she has done herself.