It could be an interesting feature if combined with treaties. Make it so that all diplomatic relations, excluding war/hatred, require the signing of a treaty and the treaty has a set amount of time until expiration. To pick an arbitrary number out of thin air, a 6 month limit. When a treaty is being signed the choices will be something like, 4 weeks, 6 weeks, 8 weeks, 10 weeks, 12 weeks, etc to 24 weeks.
