Matthew Hayden is perhaps the player with the least capable replacement, with Phil Hughes failing at the top of the order and having to be replaced by Watto. Still, he had an ordinary tour of England last time out and against good quick bowling may have struggled to make an impact.
Adam Gilchrist is the best of the three players, but had a very able replacement and wasn't quite himself in the latter half of his career. He struggled last time in England too, but with Haddin struggling to resurrect an innings from 7 you have to think he'd have made a difference.
Symonds is nowhere near the class of the others, and has had the most successful replacement. But considering that the series was lost in so few key moments with the bat, you have to wonder whether his undeniable ability to turn a collapsing batting lineup around in the big moments would have saved Australia when they were falling apart. North had a good series, but his centuries came with Australia already well in control of the game and the going straightforward. Mid-collapse at Edgbaston, Lord's and the Oval, he failed to turn things around. It's worth wondering whether Symonds could have fought back better in those moments when Australia seemed to be losing themselves the game- he's certainly done it before.