I'm not too keen on two ideas posted here :

1 - Edict for annexation : while I understand the concern for fast expansion, I don't like the idea of having to battle in the Senate (or Council or whatever it will be called) to keep a Province in the bosom of the Empire. It makes no sense historically. Powerful vassals (and sometimes even less powerful ones) ignored the will of their King and conquered/annexed provinces for their own gain, often requiring military pressure of their Lord to release them and not some court order...

2 - Possibility for FM only to create new Houses. With the limits and caps set by Zim rules, I don't think we'll see new Houses appear overnight so restricting the possibility of creating them to FM might be just a touch too much and might deter people who have had access to a RGB only from grasping power into their own hands.

Otherwise, I think it is a fine set of Rules and I particularly like the way Influence is planned as is. My main fear is that if a power blocks forms, it could enact Edicts/CA granting Influence from particular causes benefiting their numbers thus raising their power even more (I haven't decided yet if this is rather good or bad...)