i know that it has been said that "Rex In Regno Suo Est Imperator" would be hard to integrate with HIP but some of the things should be nice to final get a proper ERE system like the pronoia system described in the mods page.
Dunatoi&Aristoi system
Byzantine families are divided in two parts : military families (aristoi) and civilian families (dunatoi). Characters get a trait that give them a specific bonus and a specific malus, plus a relation malus with the "other side". If en emperor which depends on one of the two sides, his government mode changes et has an influence on all of the empire. The aristoi emperors can raise the Archontopouloi Guard, if they choose a pronoia system.
Autokrator
If a byzantine emperor get the absolute authority, he'll become an "autokrator" but will loose his aristocratic trait. I'll can fight against the both aristocratic families to restore the rights of the less powerful. He will be hated, but this situation will be very profitable for the empire.
From themes to pronoia
In 867, You'll begin with the "themes sytem" : if a doux dies, you get his title automatically, and you can give it if you want. However, be careful. If the Empire get a low authority, Doux will get a new objective : imposing pronoia (their title will become a feudal title). If they succeed, you will loose the possibility of getting their title à their death and revoke it without a malus. An autocrat emperor can cancel the pronoia system.
Dunatoi&Aristoi system
Byzantine families are divided in two parts : military families (aristoi) and civilian families (dunatoi). Characters get a trait that give them a specific bonus and a specific malus, plus a relation malus with the "other side". If en emperor which depends on one of the two sides, his government mode changes et has an influence on all of the empire. The aristoi emperors can raise the Archontopouloi Guard, if they choose a pronoia system.
Autokrator
If a byzantine emperor get the absolute authority, he'll become an "autokrator" but will loose his aristocratic trait. I'll can fight against the both aristocratic families to restore the rights of the less powerful. He will be hated, but this situation will be very profitable for the empire.
From themes to pronoia
In 867, You'll begin with the "themes sytem" : if a doux dies, you get his title automatically, and you can give it if you want. However, be careful. If the Empire get a low authority, Doux will get a new objective : imposing pronoia (their title will become a feudal title). If they succeed, you will loose the possibility of getting their title à their death and revoke it without a malus. An autocrat emperor can cancel the pronoia system.