Belatedly so apologies if I missed this previously stated in the comments...
I personally appreciate games that set down a meta/OOG expectation for players holding positions of authority as part of the responsibility of holding the IG position. These tend to center on minimum expectations of activity. I know some people feel like this gets too close to sticky entitlement issues but I've seen more than one game gridlocked by players with high positions who disappear due to burnout or real life issues or some combination of that and other things going on. There is an element of 'do I really have the time at the pace at which this game moves to do this pretendy thing?' that players tend to evade honesty with themselves about in the excitement of the position that their future self will only see as fuel to stop logging in when the burnout hits. So, games that real talk the player's ability to really give this a shot is worth the otherwise constant churn of the pointy hat in the big chair of the week.
That said.
I've seen games that tack too far into giving the person in a role of big responsibility too much free reign in how they organize their position. There are some iron willed, in for the haul players who find this stuff their absolute jam and game staff tend to love these people because it makes their lives easier. The downside to this though is that when this player stops playing or the PC dies/retires - staff doesn't have a clue what's going on because it's all in the head or the game logs of the outgoing player who may or may not be available to explain or transition any of it and much of the very high level, sensitive, intricate information that is essential to keeping one or more huge secrets in the air and going is now officially a black box.
This isn't the fault of the exiting player and more of a game design flaw.
Relationships - Romantic, Familiar, Otherwise:
I got burned twice in this department. Once pretty badly and once wasn't that big of a deal but it was frustrating to have to RP around it like it didn't happen because I didn't know how to explain it in game. From these experiences, I tend to think that there's a self-responsibility in creating a 'dead man's switch' that kicks in if the other player ghosts or things get ugly OOG. If you keep it simple and relatively blameless(e.g. 'Oh yah, Harriet moved to Cleveland to join a slam poetry society and breed labradoodles- I hope she's happy'), then it makes easier for everyone to move on.