u/FieldGlobal3064

This has to be an unintended consequence, but as the title says the changes to stack wiping low morale armies makes certain parts of the world unplayable since it takes an entire morale bar to move between provinces.

It is clear that the AI is spaming mercs now and I wanted to throw out one of the changes that is contributing to this.

You can see it yourself with your own nation if you turn AI building Automation on. That issue is that once you run out of peasants the game will mostly just not build anything and just save up money.

Thus, due to the disease changes and many nations having almost no/very little population growth for the first 250 years of the simulation, most nations are not spending any ducats. Thus, they are hiring mercs like crazy.