Makes it more likely that factions will accept peace after being defeated and generally creates more historically believable campaign development. Creates diplomatic difficulties for factions that expand too rapidly. While a successful military campaign can get you large diplomatic bonuses that can allow you to get a peace treaty, you will also get smaller penalties with both allies and enemies. The penalties are more long-lived than the bonuses. This means that constantly being on the offensive will lose you some friends, while enemies that were beaten and compliant at one time will soon recover their resolve and may become aggressive again. Short, sharp campaigns with specific objectives are more effective than long, drawn out, or inconclusive wars.
Users of Divide et Impera will get see some interesting diplomatic gaming, but the first few turns will be somewhat chaotic as aggressive AI factions all go to war with their enemies at the same time. If you survive the initial storm, the system tends to settle down and generate some interesting dynamics. Playing in Vanilla produces excellent results as well, with less of an initial period of instability.
As far as I know, this mod is save game compatible.
This is the result using vanilla plus just Desden Small World mod.
Not only is the diplomatic game more interesting and important, but the major factions do much better. In this one I am playing Pontus. Note that my allies Bythinia, Trapezos and Cappadocia are also doing very well. This is a result of having to let my partners do some of the expansion to avoid suffering too many diplomatic penalties with them. Our latest war was with Armenia. It ended with Armenia accepting to become my satrapy after offering peace plus 4000 gold. Cappadocia now dislikes me quite a bit, despite being a military ally.
Spoiler Alert, click show to read:
The situation in 242. Rome and Carthage are both doing fine and the Seleucid are slowly being expelled from the east by Persia and Media
The situation in 220: Rome and Carthage are on the point of confrontation. They are very red to each other in the diplomacy screens. The Suebi and the Arverni are emerging as regional powers. In the east, there is the continuing consolidation of a single potential rival to the Seleucid.