Thanks! I had missed that one, which does agree with your point. I had also mostly forgotten Heideran's decree, so parts of what I described as likely need to be revised in terms of that decree. It would be interesting to know when that line was put in. IE was it put in when they added 24th imperial or does it date back to the Heideran days? Its worth remembering that we aren't dealing with a static world here, what the PF says gives you a piece of primary evidence for a specific moment in EVE's history that may not be true 5 years later.
I am certainly not arguing for a usual european feudal state (if such a thing ever existed).
What I am going to consistently argue for for is a state that is dominated by aristocratic land holding authorities who resist centralization. You don't need an edict like Heideran's if you have a centralized state. That is an attempt to centralize the military, the very existence of the attempt means that it isn't centralized.
Kador had sufficient military capacity to *try* that silly invasion. That implies a major buildup of power from the "more security forces than military" of the Min of War description. That his forces were stripped from him only happened after he failed miserably. So, yes that is evidence that Jamyl is trying to centralize things, but it is also evidence that the Heirs spent Karsoth's reign building up their own power bases with an expectation of a major civil war.
Another thing to consider is that Heideran's decree probably resulted in a great deal of false reporting of ship types. I expect that there are a rather large number of Battlecruisers and "Heavy" Cruisers in the Holder Navies. And Battleships that just happen to look like dreadnoughts. And so on.
Edit:
Checking my old PF thread: It looks like that one is a change that was put in with Jamyl, the old Ministry of War description was "The Ministry of War wields extensive powers within the Amarr Empire through their control of the armed forces" so someone relatively recently decided to add a statement that the heirs had security forces rather than proper military forces.
It does suggest to me that much of the navy itself is going to be more beholden to specific holder family networks than it is the centralized authority. Because there has to be some check by the holders and heirs on the centralizing bureaucracy.
Edit2: Also, I was just reminded that Kor-Azor was fielding dreadnoughts in the Brother Joshua arc. This suggests to me that the issue is a bit more complicated than the Ministry of War blurb suggests.