I'm not sure if this is a problem with Civ in general, but I think it has to do with FFh and the Bar trait again.
This time I tried to play Sheelba/Clan that has the Bar trait. It was a huge map at Prince...with raging barbs naturally.

All was fine as I created some goblin scouts and had them scouring the map and picking off all the goodie huts.
Two, then three civs went down courtesy of the raging barbs. But, then, I noticed two civs without the Bar trait, Mahala/Doviello and Perpentach/Balserph had scores that kept climbing, caught and passed me.
I got an Open Borders agreement with both and dispatched two goblin scouts to each civ to see what was going on.
Here is the problem: From turns 500 until 610, NOT ONE barb set foot in either of these civs. The civs were building more and more cities all with improvements with busy workers doing their thing.
Where were the barbs?
This is a balance issue, I think, because you are penalized by having the Bar trait with a 10% hit to research. However, these two civs don't get the penalty, have other traits, and are not attacked by barbs. I noticed the same in another game with Lanun/Falamar.
I did notice some of the Perpentach and Mahala defenders were very high level units - they likely did attack/defend early on. But, why no barbs invading for more than 100 turns? In the Calabrim game I played I was still being invaded in the year 1000 when I gave up.
Maybe they do get attacked early in the game, but why would the barbs just stop and let them build up their civs? I saw plenty of barbs wandering around and several barb cities near those two civs.
Is it because they are evil civs?
I dunno, but I really think this is either a balance issue, or just the AI cheating, the rat!
Comments?