I've been playing Vox Populi for a while, and one thing that bothers me a lot is random AI wars. I just ignore diplomacy entirely now since it seems so useless. Luxuries are useless, and I can never succeed proposing declarations of friendship, and even if I am at friendly terms with a civ they'll still war me anyways. AIs across the world or across mountains or similarly impossible invasions keep declaring war on me even at friendly. They will many times have a couple of units and not pose a threat at all. It just makes games drag way longer than normal, since there has to be a lot more micromanagement of troops every turn. I usually play on King, but I've found the same behavior when playing on prince, and I don't play emperor because this annoyance is even greater because the AI has more units.