found this on the official forums, addressed to the community:

Quote Originally Posted by Granville69
Please have faith in us. The campaign AI team are fixing invasions and other issues. The battle team is fixing fort pathfinding and naval avoidance and boarding etc. The sound team are fixing sound issues and the graphics team are fixing display issues. We've fixed the video problems. We do have a presence on these boards contrary to what has been said. I have posted a number of times.
This isn't the Medieval II team, this is the Empire team and we'll deliver patches via steam quicker than for any previous total war game. Yes we recognise steam has created it's fair share of problems for some people but one great advantage of steam is we can get fixes to you much quicker.
I can't give you a list of every fix that's been done, because I don't have a definitive list, that is forthcoming.
btw Granville69 is a CA staffer.