I've noticed that castles only offer rewards once per day and only at one castle.
I believe the current castle reward system is unrewarding and un-efficient. It lacks the sense of collecting a daily reward, which is, what i take it for.
It would be much better both for the Player and Financial part on Kingdoms if they change this.
Making it so that, each castle offers it own reward, once a day. Adding new types of rewards to the tray*(Hides, Bracelets and possibly Honor*(Honor should not be added if already max level). Based on castle level, will improve the reward amounts.
This being beneficial on Kingdoms part, is. That, players will have more of an incentive to unlock more parts of the map to make more castles. Increasing the likely hood, players play longer. Having more of an incentive to check their castles once per day.
Making kingdoms more relevant on their minds.