You should not set the item in the Ancient Ruin near Martinus's city with Magic Relay ability. Player can abuse that ability to summon a lurker to the dwarven city before the cleric can open the path between.
A question, what's about the girls underground with the Yeti (place where a lot of spider web is placed)? And some ghost in the dead end of the corridor where bromoth hides ? they are just parts of the story, nothing concerns game play ?
In the city of Cordian, you should give player a message that they have to chanlenge the heroes around to win the greatest weapons of the Titan. In my game, I rarely fight guards if they are the same alignment as mine. Even dragonian and nomads city, I did not conquer (kind of respect game story).
Putting some magic catalyst around does not make sense if you dont give some reason for this. Besides, this can be abused, before an important battle, player can capture several magic catalyst to have more CP. Five MC give the wizard 250 CP plus 90CP (lv5 + casting chamber+magic specialist from the item). This is too much !! Remove them or set some strong guards there is better than giving out for free
When Marcus learn the teleportation spell (Monastery Association), you should teleport the ChaoLord to an unreachable place (a tile surrounded by shadow void for exemple). This avoid player come back to the Chaolord and try to cast bind summoned. Such unit can play an important part in game, especially at that state of the game.
In dwarven kingdom where Marcus learn another level of magic spell, I don't see any exemple like the previous ones (like freezing water, teleportation, razing...). And for each spell, you mention that they can be used only once. How ? In battle or in in the world (global)? Player can cast that spell at any moment or at a specified moment ?
The conversation with Tara (girl in the water fall, near elven southern port) does not go well with the one with Grumpy (?, I dont remember well his name, a dwarf in elven land). She asks Marcus to tell that guy to come if he meets him, but when Marcus meets that guy, the conversation is just how this dwarf is crazy about Tara. Nothing mention that he should go to waterfall to meet Tara.
The resurrect event. The message appear when Marcus dies that he can be resurrected only once, but I see in the editor that it's set to always. May I suggest you can either leave it as always and change the message or set it to once and if Marcus dies, players will miss some events because he's not there anymore. The 2nd is more complicated but sounds better and warns players to take good care of Marcus.
Can you give the backup city Forcefield ? Being very limit in number of ressources, it's very frustrating when being cast Plague upon one of the cities. In my game Wortan keep casting that spell until my city becomes an outpost with almost zero inhabitant. But on the second time, when city gains back its population, he does not cast that spell anymore, and i'm relieved
Personal thought: I don't like moving around the recruitment sites you placed as living places for inhabitants and find nothing in there (deserted), although some do have units to recruit. It wastes a lot of time (Movement point). There are structure tiles for designs in 1.4 patch, and I see that you did use them, why don't you use for all but put some empty house ?