is it me or there's a rather fatal flaw in the diplomacy system?

I'm wondering. If someone attacks an ally or protectorate of mine, I have the option to defend them. Though, there's a rather big flaw in this. If i want to defend my ally/protectorate (especially if they're small and under attack by a major power) i have to go on until i completely annihilate them, because if i chose to heed their calls for peace (or to offer them a mercyful peace) I have no way to force them to make peace with my ally, and if I didn't turn them to ashes, they might manage to beat my ally.

The same goes if i ask all my allies to join me in a war against someone. If i ever decide to solve things peacefully, I'll basically be betraying my allies that will STILL be at war with my former enemy, without me having any chance to do anything about it.

Honestly I find the lack of the "demand to make peace with" option rather grating (especially because I find war to total annihilation rather unrealistic, it happened quite rarely historycally). Am I the only one?

yeah...one of many my friend

Diplomacy in NTW is only good for money aka trade agreements. Forget everything else, I just want markets for my merchant ships.

Yeah, that's the biggest flaw with the diplomacy system that comes to mind. Would be nice if you had a chance to influence countries as well before a declaration of war is made. That way if your longtime ally and closest trading partner is going to attack your insignificant protectorate you could dissuade them before it happened by threatening military action, a trade embargo, etc.

I completely agree. I hope they fix that in time for Shogun 2.