Shropt
Super Freak
All of Hurt's story was written for Eccleston, when Eccleston wouldn't come back they just re-imagined that another Doctor fought in the Time War and rewrote it for Hurt.
That wouldn't have worked at all with the way the show played out. Eccleston's Doctor was always happy. He even enjoyed when he was in the most danger as he couldn't wait to find out what was going to happen. I loved Hurt's Doctor where he was just so beaten and downtrodden, even before he killed his people.