Meh Defoe is pretty damn inconsistent and I don't really think he's capable of scoring regularly against the best teams. Rooney on the other hand is clearly England's best striker, without him up there we really lack enough quality in that area. He's a must if we want to do well, some carthorse beanpole like Carrol will not cut it against defences of real quality. That said, we need to play 1 up front with the likes of Walcott, Young, Sturridge, Lennon and Wellbeck playing off him.
In reality this England team lacks the quality it did a few years ago and leaving out Rooney would leave it too lacking. One good thing to come of this lack of quality though is that it means Hodgson has had the freedom to play in a far more conservative style.