You could be right.. How about adding a slight modification again? This cooling off period will put many former allies at war with each other and make the wars interesting again as well.
You cannot ally with this realm because you are ally recently.
This is going to cause paranoia because realm A previous ally with realm B. But now after the duration expire, realm A cannot ally with realm B, realm A can only ally with other realm it not allied with before. So in case of war, realm B at least got an insight into realm A due to they both are ally before.
Although I like the idea of limiting alliances, I'm not so much a fan of forcing war between them automatically.
