So, in light of the 3.9 update, a long-time (but not oft stated) gripe of mine resurfaced. The alliance mechanism in the game seems virtually meaningless. If I'm allied with another faction and they are attacked, big deal. Doesn't mean anything for me. But shouldn't it?
I'm not sure how much more the game is slated to change, but it'd be great if the devs could make alliances more nuanced and require a little more effort than just, "Hey, we like each other, let's be allies and keep liking each other but not do anything for one another. At all. Ever."
If an ally asks for aid and its refused--should they be able to break the alliance? Maybe they wouldn't after one refusal. But what about after several?
Should alliances be premised on some kind of mutual benefit (% of GDP toward alliance, % of military, etc.)?
Should espionage be partially shared?
Should allying with a current ally's enemy (or certain level of dislike; maybe not warring) cause problems with the current ally? Should they threaten to step away from the alliance before you form the new alliance with their enemy?
It would be nice to have alliances carry more weight.
Maybe this is GCIV territory. Maybe implementing something like this in GCIII is like R&D for GCIV... 
Just some thoughts.