I think Australia's tactics must bare part of the blame. When you have 5 fielders saving 1 and another 3 out on the boundary it doesn't aid high scoring. The plan is to bore england out and to some extent they have been successful. Stick it outside off and wait, and wait and wait. England for their part haven't worked out a way round it, or prefer to wear Australia down. Runs came at Lords in the final session of Day 3 as Australia grew weary and I expect the same here by afternoon or evening, if England are still in. Problem is it makes tedious defensive stalemate cricket in the meantime. Both teams are entitled to do it but it takes a long time before the bowling side cracks.
England have set ultra defensive fields all series, and it is considered "professionalism".
Australia set defensive fields predominantly for Pietersen (who was gently patting away half volleys), yet, they (Australia) must "bare blame".....riiiighhhtt.
England's tactic throughout the series has been to bore Australian batsmen out, as they know Aussies get impatient when they are not hitting boundaries.
England have also (by and large) batted conservatively throughout the series looking to build rather than pillage.
The more professional team has won the series. Easily.
You will not be getting all these dry, dead, spin friendly tracks in Oz though.