Captainspire wrote:2. Allies flee when they have the advantage but help when they have no chance.
This is the most aggravating. In a combined effort to stop an invading force, when our combined fleets would be able hold them off, my allies run to the next star system, leaving me out numbered. Yet, when they have barely any ships in the system that would make little or no difference, they stay.
I can imagine how irritating that could be. I wonder how feasible it would be to make different allied empires coordinate defensive fleet plans, like intercept and guard missions. Or it might be enough to just factor in (present/incoming) allied ships when planning attack or intercept missions, instead of actual coordination of fleet plans.
I don't remember if the AI factors in the presence of allied fleets at all. I don't think it does, and I'm guessing what you're seeing is the AI deciding that it doesn't have sufficient strength to fight so the ships get reassigned to a guard mission. Of course, the only way to know for sure why the AI does anything is to reproduce the scenario in-game and examine it using the AI debug tools.