Shadow-war has a decent write up and details of the leaked patch notes for 1.3.1 that briefly appeared on the EU forums. If you want a heads up on what 1.3.1 is probably bringing us, that's a good place to fill your boots. Leaked patch notes should always be considered far from gospel, but these ones look pretty solid.
Bug fixes galore and what appear to be excellent changes to the city siege system. Lets hope.