I mean, Mzali's leadership is evil. You are dealing with people at every turn who are complicit in a state that is fond of public executions essentially on a whim, with myriad instances of oppression and violence. Those people being willing to play nice when the Magaambya when it suits...
Right. And the stated goal of the first half of the adventure is that no matter how evil the leadership is, diplomacy can engage with it and moderate it. Which is good, and very in-theme for this adventure path.
Then they try to kill all your friends in the Golden City and you end up having to massacre the armies of the city you just negotiated with out of a sense of constructive engagement.
The problem isn't that the leadership of Mzali is evil (It's not great, but it isn't the main problem) the problem is that they are *expansionist*, at least in this AP if not generally. They are actively trying to conquer and/or destroy another city. Long term gradual diplomacy doesn't work when they are actively plundering and murdering.
As a PC I think you are right to ask "what was the point of all those weeks of politics if we just had to kill their army anyway?" I think as written a few of my players are going to start making Neville Chamberlain allusions.
I'm a big believer in encouraging PCs to not use violence as a first resort and everything about this chapter of the AP is all about that... until the finale fight where you kill the army and avatar of all the NPCs you were being nonviolent about for the first half of the book. The AP give you no choice but to wage war against the people you just negotiated with or stand by while they murder the Golden City.
I just don't think you can have it both ways without giving the impression that negotiation just delays violence it doesn't prevent it. That *really* seems to miss the point of the Adventure Path
Just my two cents, but I'm really smitten with this volume, and see my group enjoying it.
I'm enjoying it as well, but as this is supposed to be a GM advice thread rather than a debate about general story structure... my thought would be to NOT have the invading army at the end of the book be from Mzali. It creates too much conflict in a place where the PCs just spend a ton of time reducing conflict. The Expanse has a long history of invaders and plenty of other groups could find the location of the Golden city and try to invade it. Perhaps the "map" the PCs found is seen by the wrong diplomat from another power in Mzali, or let a porter or researcher back at the school find out about the expedition and carry that knowledge to the wrong ears.