I posit that they would take Birth Order out of it for the most part, or make that a choice of Marquis on up.
Example: My father, the Late Marquis Sidur Haski, has three of age (I define legal age at 14 imtu) children, My older Brother (who is now Marquis, and a Naval Commander) Me and My Sister. When we all came of age, my father installed each of us on a Barony in System. I got the Third Sidur Haskian moon of Sidur Haski Prime, Saano, the drydock moon. And so , my title properly is Baron Saano. These Entitlements are directly created by my father, and are all sub-fiefs of the Sidur Haski Holding.
Beyond that, you get into the area where people potentially can get killed in bad political appointments. I would think that Marquis+ would all be Merit Titles of Aristocracy. I think by the 57th century the folly of true hereditary monarchy would be discovered, and avoided. THis may work like this to weed out any Caligulas or Neros.
Advancement beyond Barony requires Moot Support of the Patent. This brings the noble in question into close scrutiny by the peerage to see how he or she is as a person. How he or she is "Socially". After a few State Functions, which would be designed to "test" the noble, it would become clear who is insane or corrupt, and who will be a competent ruler. It can be something as trivial as the other nobles merely liking the new noble socially.
A descent into corruption later on by a noble in that case would be that noble's personal choice. Hereditary Rulership needs its thorns removed.
I have played noble characters, run noble characters, and even tried to start an all noble intrigue game. We did not even get out of character creation, as it was found out that the titles and holdings add roughly another 200% to character creation. Being a Noble should be hard. They should all be forced to work for the Peerage, and the peerage should be a self checking entity. The social mores of the Imperium may seem foppish or elitist, but they are designed to weed out undesirables. (The Greedy, The Bloodthirsty, etc.) Those unwilling or unable to play the game, soon find themselves censured or worse.
All of the above benefits are tradeoffs. Yes, you may get an Industrial Concern, but think of how much it would take to administer. Even finding an agent administrator would be a job in itself.
There are some, like the cash ones, that are basically a free ride, but bear in mind that nobles MUST maintain a lifestyle that fits his station. That money can get eaten up pretty quick.
Also, consider the REferee fun you could have with Political Marriage. My favorite was Count Rruaro, a Noble Aslan Citizen, who tried to remain a bachelor, but was compelled by the Hirate and Imperium to marry. 15 times! He had six traditional Aslan wives (nobles that did not even speak Galanglic) and the rest as modern Aslan Females.
So being a noble should be a challenge. Marquis and beyond should require work to stay at your station in life.
, so I am probably totally off with everything I come up with in this area, then again, in 3000+ years, and Vilani influences, who's to say that I'm not right? (OK all together now... "You're not right"
