Del Potro is also a threat for Fed in a QF (actually he is a threat for everyone, but he did beat Fed back to back in Basel and WTF). He is also more consistent than Berdych, who could also be in a day off (altough he was solid both in 2011 and 2012). Tsonga did have good result in Australia too, but he isn't consistent here.
The happy one will have Tipsarevic in QF and Ferrer in SF. Final will be tough in any case.