Not sure if this has been discussed before, but one idea I like is to make the current Regent actions require both a Character action and a Court action. This allows it to represent the efforts of a combined domain, rather then the current system where a regent can perform three actions without any assistance.
This makes a reasonable court more of a requirement for even moderately sized domains. Perhaps more interesting is the possibility for character focused domains to not pay too much attention to their court. This would apply to Wizards and for Adventure eager domains such as the Wardens. Similarly Vassals with a limited (or non-existent) court would be limited to supporting their liege with character actions, rather than spamming with a huge number of regent actions.
This does of course change the actions system quite drastically, and the cost of court/domain upkeep will have to be balanced against action costs. Perhaps the standard 1GB action cost would be considered to be included in the continuing upkeep. It would also be possible to differentiate between actions requiring more effort, thus taking more than one action. Getting down the path of Action Points here, so I'll stop rambling before I get to carried away.