Hey CA crew,
I've got an idea to make the diplomacy a bit more versatile and potentially more interesting.
Just before I begin, I wanna state that I play campaigns pretty much only on legendary difficulty, so my perspective is based on such experiences.
Currently in diplomacy, we have the option of "join war against" a third party during an interaction with a neutral faction/ally/vassal. This is absolutely great for the purpose of singling out an enemy faction among a coalition (particularly against factions like Karaz-a-Kazak, which usually steamrolls like hell even in early game and makes tons of alliances with the other civilisation races), or simply drag another faction into a current war.
My suggestion is to add an option of "make peace with" a third party during an interaction with a neutral faction/ally/vassal. It is a counterpart to the "join war against" option and they complement each other. The reason being I always find a faction/territory that I would like to conquer/ establish a relationship with is being smashed by a third faction, and the only thing I could do to secure the territory is to rush against the third faction, which is a bit of a nuisance especially in the early game when the economy is yet to be developed and therefore only one/two armies could be fielded at the time. The "make peace with" a third party option would provide players with an additional diplomatic mean to secure territories by deterring the third party from invading the faction players would like to conquer/establish a relation with.
Another reason being when I'm in an alliance, my ally could be really aggressive, and declare war on a lot of factions. Since we are allies, the diplomatic penalties against the third party applies to me, followed by the deterioration of relations between me and the third party, and eventually the third party would declare war on me. This is alright when I've got only a few enemies and it is somewhat expected in an alliance anyway. However, when the third party is situated somewhere far away with a faction/factions separating our borders, they would send armies across half the world just to pick a fight with me (somewhat like the Crooked Moon Mutinous Gits in a Crooked Moon campaign), which becomes a bit annoying, considering the third party is rarely penalised for trespassing factions that it has no military access agreement with, while the player is penalised heavily for it. The third party could remain at war with me for ages as I couldn't reach them, and they could keep sending waves of armies to fight me, which further deteriorates the relation between me and the third party, and the third party's allies. This goes into a downward spiral where you're not getting out of any war when a distant faction declares war, which is pretty frustrating and reduces satisfaction in playing a campaign.
The "make peace with" a third party option would nip the problem in the bud. The player could get their ally/ the third party to stop fighting a war against each other, and therefore avoiding the diplomatic penalties between the player and the third party, as well as potential wars later in the campaign.
Since I play on legendary difficulty, I do expect the AIs to have cheats and bonuses. Nonetheless, the aforementioned situation gets out of hand whenever I ally with a faction with the purpose of strengthening my position, only to find that I am being dragged into more and more wars by my ally and being weakened because of that.
The "make peace with" a third party option would provide players with more control over securing territories and maintaining good diplomatic relationship with a third party particularly when being in an alliance, which I believe would ultimately leads to more satisfaction in playing the game.
The execution of the "make peace with" a third party option might be a bit tricky though. Diplomatic interactions are always two-way, the player against an AI faction/ an AI faction against an AI faction. Since trying to stop a war between another two factions is strictly not two-way interactions on two occasions (not player against AI #1 + player against AI #2 then, but player against both AI #1 and #2 at the same time), the "make peace with" a third party option could be made available only if a three-way diplomatic interaction is made available.
It seems TW:3K might have a similar diplomatic option in place, unfortunately I don't own TW:3K so I'm unable to comment on that. If it is true, it might just be easier to incorporate such mechanics fully or partially into the diplomacy of Warhammer ii to spice things up.
On a side note, going back to the issues with being at war with a distant faction, consider increasing changes in diplomatic relation through actions with a proximal faction, and decreasing changes with a distant faction. It could be done by incorporating a factor of 0.1-1.0 by considering the displacement of the closest 2 settlements among two factions, and the number of other factions in between the 2 settlements. For example, the closest settlement of mine is Iron rock and that of faction A is Black Crag , the two settlements is immediately adjacent to each other and there's zero other faction in between, therefore the diplomatic factor by geographical location is 1.0. Assuming I use the break wall action with an agent on Black Crag with a gross diplomatic penalty of -10, this number is multiplied by the factor of 1.0 and therefore the net diplomatic penalty is -10.
Considering another scenario. My closest settlement is Khemri and that of faction B is Kislev, and there are 5 other factions in between, the diplomatic factor by geographical location is 1.0 - (0.1* 5) = 0.5. Assuming I use break wall action with an agent on Kislev with a gross diplomatic penalty of -10, the number is multiplied by the factor of 0.5 an therefore the net diplomatic penalty is -5.
When the two closest settlements are separated by sea, like Estalia-Lothern or the Awakening-Lothern, the factor could be set at 0.5, so factions in their respective regions of Old World/ Ulthuan/ New World would primarily focus on their own regions before meddling in the other parts of the world. Depending on playstyle, factions like Dreadfleet in Vampire Coast should not have such factor applied as I assume the faction is meant to be played by invading different worlds concurrently.
This way the distant enemies could still send in a couple waves of armies initially and are easier to make peace with after defeating these armies, they would still present a certain level of challenge without being a nuisance over a long time.
Cheers to all the CA crews and whoever that has taken the time to read this long post. Here's a potato!