What would have happened if Harry had not insisted not to go to Slytherin during the sorting process?
Or what would have happened if the Sorting Hat didn't listen to Harry?
"You can become something great. You know that Slytherin can help you to achieve greatness in just a moment's notice. There is no doubt about it."
Let's assume that the Sorting Hat never makes a mistake.
Will Harry still be friends with Ron?
What about Harry and Draco's relationship?
Will Harry still have so many opportunities to make mistakes under Professor Snape's supervision?
What choice will Harry make when he is in danger?
What different changes will happen to Harry's personality?
How would Harry accept Slytherin friendship?
Will Harry still be so disgusted when encountering dark magic?
How will Harry fight against Voldemort in the future?
Note:
No smearing or whitewashing, sticking to the original characters, no OOC characters, it is a complete series with imagination.