There's a relatively common event where a group of bandits will attempt to take over the province. This event is prevented from happening if you have a PD of 4 or higher.
1 is definitely the minimum, but popping it up to 4 costs just 10 gold and will prevent that event from happening, even if the resulting bandit horde could potentially have knocked over the PD. Furthermore, things like heavy cav provinces will get their first cavalryman PD at about 4 points, which can help out in certain situations.
Also, eunuchs. Oh my god, eunuchs. They deserve their own goddamn shrine in the pantheon, right next to MA Man's monks.
EDIT: Lately I've been messing around with LA R'lyeh, and I've gotten to thinking about some things... Personally, I think the nation could do with pretty much a full-scale rework.
We see nations that enforce or at least recommend certain negative scales when playing as them. Things like Lanka or to a lesser extent Pangaea push for Turmoil scales, low-resource nations and EA Arco do well with Sloth, Ulm and Man dig Drain scales, and pretty much all the popkill nations are a death scale no-brainer (except for Asphodel, because they're a special little snowflake), not to mention several nations that can make good use of heavy temperature scales one way or the other.
...but no nation has any use for Misfortune, or anything that really counteracts just how nasty a scale dump that is.
LA R'lyeh is in effect "just another popkill nation" in its current incarnation, but with the added problem of having the freespawn require both upkeep and supplies (note: DO NOT build coastal castles as LA R'lyeh... You still get the freespawn hybrids as MA, but these cost 6-8 times as much upkeep as the regular dreamers and madmen), something that's doubly problematic not only because the population and thus income+supply base is steadily going down as your demand steadily increases, but also because death scales are kind of a necessity as their population reduction effect is a drop in the bucket compared to just your basic dominion.
What if, instead of a straight up popkill, R'lyeh's dominion tied more heavily in with Misfortune rather than Death? Random cataclysms, horror attacks, suicide cults, it all still plays into the apocalyptic situation of the dreamlands, but without just being "Oi, the stars is right, innit? Guess I'm gonna catch the void-flu and drop dead, so I will". This also opens up the possibility of taking growth scales to help offset the supply/income issues (and MAYBE even just open it up for a little bit o' the old blood magic, because I feel this Ftaghn hasn't got nearly enough human sacrifice going on). Give the freespawn insane cultists 3% fortune teller or something so you can help offset the dangers to a couple prime provinces and then basically just hold on for the ride as everything else eventually tears itself apart through the madness of the eternal void.
You still get a pretty dangerous dominion, it's still not exactly great for your pockets or your people, but I personally think it would tie in better with the insanity of the dreamlands, and also make the nation a bit more unique and stand out from the ranks of Ermor/Lemuria.