From the DA Beta 2 journal:

+ When a trade between players is enacted, AI player won't see any player for 8 more weeks (any player not just human). This should dramatically change the way trade occurs between players. Previously, the AI traded techs like crazy.

If I understand this correctly, I'm concerned about the possibility of cheese. Couldn't I simply go to a civ every eight weeks and give them 1 BC or some minor tech, thereby preventing them from talking with anyone else for the entire game?

Also, since treaties such as cease fires take place in the trade screen, the player could be prevented from ending a war (or convincing friends to help him out in one) because another AI civ already traded some minor tech with the civ in question.

I'm okay with the idea of slowing down trade. I also don't have a problem with not allowing the player to talk to a civ every turn. I am concerned about not being allowed to speak with a civ because someone else already has.