To talk about LN as an example.
LN is an example of a realm that won, but lost at the same time, the challenge is gone. In the last 1-2 years all those who had a different opinion than fulco were ousted, the moment malus and he decided to work together was also the moment there were no real enemies left. Those that remained either had no true power or were nice and calm followers. It's an ideal situation for a ruler, nice and comfortable position, no threats and boring as hell. The Lurian area should consist out of city realms, who constantly plot against each other and forget about the rest of the continent. Battles over regions, rather than cities, rebellions when realms become to large and a war not further away than a couple of days. The moment you have to march for a week to a battle truly means your enemies are too far away. You will have a battle once every 2-3 weeks, for who is that fun? Heck, the entire dhara war, equipment damage and starvation were our largest enemies as it took ages to travel.
And let us look at realms in general. Small realms who want to expand normally have to fight a much larger realm, a realm that can smack them with ease and likely with good allies. Large realms don't have the need to expand as they have barely the nobles to keep their current amount of regions. The result that there is little reward to fight. Best case senario you gang bang a realm and get a few regions, worst case senario you lose. But always you will need months to recover the regions in which is fought, long boring months.
Add harsher penalties to realm sizes, limit the size of alliances/federations and increase region recovery. And reconsider an option as TMP when realms after those changes are still hesistant to go to war.
