For nation mods, I can recommend:
- Tomb Kings (by llamabeast)
- anything by Burnsaber
- anything by Sombre
If you're interested in nation mods.....
Also, look up the Mark of the Champion mod. It transforms the Champion's Trident into a flashy helmet, which makes the Arena combats slightly more valuable than otherwise.
Lastly, although they aren't technically
mods, you might want to look into a NI (no independents) map. The NI maps make a big difference in single-player games. Instead of recruiting hordes of stupid chaff, the AI is forced to recruit its national troops ... which usually results in a more interesting game.