Just weeks before the first Ashes test, the Australian cricket board made the wise decision to get rid of Mickey Arthur as team coach and replace him with Darren Lehman. In my opinion this was necessary to make Australia a bit more competitive in the series.
Arthur was always the wrong fit for the Australian job, as a South African he was never accepted by the players or fans. His authoritarian methods made the players feel like they had gone back to school. This was highlighted in the disastrous tour of India where four players were suspended from a test match for disciplinary reasons.
It can be argued that the Australian cricket board also didn't trust Mickey Arthur by allowing the captain to be part of the selection committee. This resulted in players not being able to confide in Michael Clarke in fear of being dropped.
With the appointment of Darren Lehmann the captains selection rights have also been dropped. This means that Clarke is now free to concentrate on his own performance aswell as team building. His methods seem to be more relaxed and more accepted by the players. He was a fighter as a player and will be hoping to install some fight into his new team.
His old school methods seem to be focused on making the team feel as if they are playing against the whole world. There is nobody who could install this seige mentality as well as Lehmann. The knowledge he amassed while playing in one of the greatest international sides will be passed onto the current side.
The effect of appointing a new coach can make teams play better, this can be witnessed in football when new managers come in. If the warm up games are anything to go by the Aussies are slowly coming back into form. The bowling is their greatest strength, they should cause England some trouble.
If I were to predict then I would say England will still win the series but it will be alot closer than it would have been in Arthur had ket his job.