As much as I am very much looking forward to EU4, I am really curious as far as alliances go. In EU3 an AI can only have 3 alliances + vassals. Usually when you begin a game the AI throws alliance offers left and right, and you might accept some offers and others you do not. If you do not accept them, then you (least after my experince) will have a hard time making new allies, as many of the AI stick with 3 alliances, which is their limit. So even though they love you, and you love them, then an alliance is not possible.
How will alliances be handled in EU4 compared to EU3?
How will alliances be handled in EU4 compared to EU3?