I dont know all that much about Edmund Crouchback. He seems to be a more peaceable fellow than his brother but then again who wasn't more peaceable than the Leopard of England?
It would probably be safe to assume that Crouchback would not launch on any such ruthless campaigns against the Welsh or Scots that Longshanks did and it would also probably be safe to assume that parliament would not get the reforms it did in OTL without Longshank.