I think you need a benchmark set for ratings, because in my opinion Trescothick whilst a quality batsman is being ranked a little too highly here. For example if say Bradman was 10/10 for everything, then someone like Lara or Tendulkar was a 9/10 for nearly everything, so someone like Ponting would be around 8/10 for everything, making Trescothick more around 7/10 for tests, Odis and attack and then defence would be around 5 or 6/10.
Leading all the way down to say someone like Monty Panesar who would be around 1/10. So you have to get the scale right instead of following the standard mistake when rating out of 10 in which nearly everyone is rated from 7-10 leaving the 1-6 as almost useless.