I was thinking about the new friction aspect of the treaties and I think it would be a good idea for rulers and ambassadors to have the option of increasing friction. It would take the same form as treaty maintenance currently does, just do the opposite. It shouldn't be an all powerful end to the treaty, but it would provide significantly more work for ambassadors who seek to maintain it.
This would allow rulers who are engaged in what they consider unfair or unwanted treaties to wriggle out of them without a formal break, and it would make the post of ambassador much more important and powerful.
As far as reality goes, this would provide a reasonable basis for the existence of friction in treaties. currently friction simply arises over time, but in real life and in medieval times friction arises because one or more parties have a problem with the treaty. In consideration of treaties that arise after one realm surrenders, it is often the case that the treaty strongly favors the victor, but with this feature, if that favor is to strong there can be a second battle diplomatically as the ambassadors and rulers squabble over the legitimacy of the document.
