Also it´s better if there is sexual tension between them anyway, so things would play differently;
Draco likes Harry because not only was he the boy who lived, but he turned her down when she tried to be friends after insulting Ron and Hermione in the 1st year. This animosity became an obsession which became a crush, but because she's haughty and they've not exactly on the best terms, she thinks that tsundere teasing is the way to get her man.
I'd say in the second book, Harry shows outright disdain for her after learning that her remarks to Hermione were racist. Then in the third book she seems to try and grow as a person.
She approaches buckbeak to impress Harry, then when she gets hurt her father has the beast killed despite her protests (she knows that would only make Harry hate her more)
in book five she helps Dumbkedore's army, but doesn't go with them during the final battle because she knows she'd face her dad, and she hasn't grown that far from him.
Then at the start of 6 she's acting super cold to Harry and company. Like she used to back in books 1 and 2. This fuels Harry's obsession to find out what was wrong with her. At the climax, she reveals to Dumbledore that she has to kill him or Moldy Wart will kill her and her family.
Basically, having her grow close to Harry makes her arc in book 6 more emotionally impactful