I'm quite enjoying the latest version.  It does feel much more challenging, but my current game ended in an interesting way, and while I am not sure exactly what to do about it, it does feel a little bit broken.

I was playing along, doing prettly well, only having met one AI opponent.  He didn't like me, but we'd done some trading, and nothing had happened yet.  I was trying to ignore him, and just work on my empire building.

One turn I suddenly got 5 messages saying that because I was at war with their friend, various AI nations were declaring war with me.  Each of these messages were of that nature, until the last one, which was the one AI I had seen.  He didn't say anything about his friends, just that he was going to war with me.

Now this was fine, except for a couple of things.  First, his message was last, so I was initially a bit confused about which friend the first five were talking about.

Second, I hadn't met the other five AI's yet, so it felt very strange to get that as my first contact without ever seeing them.

Third, five or six messages in sequence like this felt quite dramatic.

Now, I think what happened is some AI code that says if someone declared war, other nations that are friendly with him/her go to war as well.

Here's my suggestion as to how to make this feel less broken;

First, it shouldn't be a boolean.  There should be a chance each turn of going to war with a friend's enemy in this manner.

Second, it should be with a friend, not just someone the AI is at peace with.  I know that at least one of them wasn't a friend to my attacker, as he declared war on him the next turn.

Third, It shouldn't happen immediatly.  There should be a grace period of at least a few turns before they all start piling on.

As to how this ended my game, well, I wasn't prepared for it, and went down pretty quickly.