How about introducing berserk raids for kingdoms and game? Players can use a new building to change their scrolls to berserk scrolls. They will need
2x scrolls and orns+other stuff to make them.
Berserk raids will give 3xXP, orns and gold, 2x item rewards and 2.5x material rewards. Will have 2x stats and will have 2%-5% higher chance to get better quality item.
This will bring a new challenge to the old players and also help them get more mats and better quality items for that extra risk.
Cost can be increased to 3x the Korns or scrolls to make one berserk raid