To be fair, after glancing over the whole thread, it's hard to know what would constitute a 'specific barb behavior' not already covered by your analysis or these comments. Very anegdotal: It seems that barbarians are doing a calculation on their 'health remaining' after a potential attack, taking into account units they can see and they will perform the 'move out and move back into camp' only of one of these units is an unreachable ranged unit. Basically, they behave as if already too wounded. So far I've definitively seen this behavior with my 2 archers advancing toward a camp, but it might've also been the case with (full health) scout and archer. Also very anegdotal: I think barb tech works the same or similar way as in CIV4, as in: if you don't reveal horses, they won't spawn horse units (will happily spawn galleys tho).