negative example is in my opinion arcarea, that quickly moved from long-negotiated peace to war, even if she was not party directly involved in ga-cathay troubles, in my opinion just to use favorable disposition of military forces. ordering attack and than declaring war 15 minutes before turn-change is one of my the least respected things in the whole game, and falls into similar category. there is no any rp-ing justification for use of diplomatic buttons for military tactical purposes, in my personal opinion, that just leaves bad taste.
This shows WHY this is a bad idea. Arcaea declared was because we were treaty bound to defend OW. Yes it had little to do with the Cathay-GA issue, and had everything to do with GA marching through Cathay to attack OW. See how easy it is to assume something has no RP basis simply because you aren't personally privy to it?
in these old times, did any real change really happened within days? as far as i read, english king accepted that middle solution just to formally end too long war, while even being aware how things will go later, he could not give up everything in one step, so that could possible me more in favor of proposal
How could it when it took weeks simply for a message to get from England to France? You have to extrapolate relative time frames here. In the real world it might take weeks to march a large army the distance between our regions, we can often do it in 12 hours and have instant messaging. Given such constraints, several diplomatic changes in a few years is very rapid
The only limit would be that quick diplomatic changes could not be used for military tactical operations and too-easily agreed gang-bangs.
I've never seen a "gang-bang" that was set up in a few days. Sure the act of lowering diplomacy might only take that long, but it was likely organised long before. So all your change would do is let the target realm panic and worry for longer before the attack. If it is a true gang-bang that everyone seems to fear, then it is unlikely the rulers will be swayed to attack for any IG reasons. If it is not, well then there is really nothing wrong with several realms attacking another for IG reasons, except that it can infringe upon personal ideals of fair play.
particularly bad was is, for instance, when alliances A and be fight, alliance A suffers series of losses, than some realm that are part of it quickly change side, and we have gang-bang war.
Throughout history there have been those that would change alliances when it became clear they would lose. Often those realms only allied in the first place because they thought they had picked the winning team. It would indeed be odd to see a strong ally do such a thing, but then allies are not always closely aligned, no matter how long the alliance has been in place.
if harakiri is not expected from european rulers, they were at least expected to die in battle, or go to exile to the end of their life after they are defeated, not to quickly change diplomatic stance and stay on throne.
Depends on the realm and the particular age. While many Kings did fight on the battlefield, certainly not all did. Yes losing completely would result in exile, but the eqvalient in BM would be the realm being taken over, revolting or something of that nature, which also has the potential for exile. A European King was unlikely to face exile for losing some battles. Again look at the 100 year war, France lost several battles early in the war, and land but the royal family stayed on. King John was even captured by the British, but was released and returned to his throne.
One more consideration. One thing I have noticed is the use of diplomacy setting by a third party to either prevent a battle or to limit who fighting in one. For example If Realm A is fighting Realm B and C, and a fourth realm Realm D is at war with realm B but has peace or better with A and C, then realm D can prevent realm C from fighting in large battles against realm A. Under you system such tactics could be used long term, and it would take realm C some time to lower their diplomatic stance to counter this.
