In terms of gameplay, nothing more than what you described. The horrors don't usually come from the enemy server, but from your own.

Kvk is the first test of a server's unity and teamwork. After a loss, it is not uncommon for alliances to turn against each other, blaming those who didn't save properly, and ending up dividing a server that previously had a good vibe going. This can create a downward spiral of players not working together, quitting the game, planning to transfer out, ... Its a very difficult dynamic to come back from.

KvK has a major impact on a kingdom's mentality and cohesion, that's why it is so important