well, when you have a Vassal that is a mere hindrance, you shouldn't wonder that friendly means actually, I hate you and am going to attack you, but bluff you I am friendly, so that you suck up to me even more...
I have to say, that it's fun to play with this team for sure, but this game has been a utter disappointment for me in terms of what we can achieve in such a game on this difficutly level. First of all, we have been just lucky, that no AI decide to simply wipe us out early. We actually gained a lot of ground by playing pretty well.
Things started to turn when we decided to get a vassal. Since that concept is so crappy, it should just be abolished.
Next thing was the long war we fought. We fought brave and smart, but ridiculous WW and upgrade concepts yet again made this experience rather unfun for me.
Now we get a friendly Civ to declare war on us, because the Civ 'doesn't like us enough'

In fact, this is so wrong, the fun element is long gone for me.
Let's see what we can carve out here in the end, but this SG has achieved to simply confirm my feelings about the game. It simply lacks the fun factor of the series. I will gladly wait for Civ5 or a surprise turnaround with a new expansion. As it is, the game is broken in so many way...
And as we can see, all those really admirable efforts put into 'better AI' cannot remove that something is wrong here...
(I know my post will attract some flaming...go ahead)