I've really been getting into Peter Wilson's book "Heart of Europe", and he presents the case that the Holy Roman Empire never was an attempt to create a unitary state, nor did it ever see itself as one or aim to become one. Rather, it was more of a constitutionalist "estate-state" that was able to maintain a base-level of imperial administration while maintaining the "Germanic Freedoms" of the northern princes and the autonomy / wealth of the Italians.
Given what I know about the early modern era (and I'd especially love it if anyone could expand/correct me on this), even France and Spain weren't far ahead of the constitionalist structure of the HRE; both states were a jumble of individual duchies that all retained significant constitutional autonomy. From what I have read, even as earlier French kings began to accumulate and integrate new titles into the French Crown (ex, Normandy, Toulouse, Aquitaine, etc), those regions were still treated as distinct entities that retained a lot of their former legal institutions. Taxes weren't uniform, nor were inheritance rights or court systems, etc.
So, on to my question: How could the HRE evolve into a more cohesive (but not unitary) constitutional structure? Basically, could the HRE evolve in a way that the Imperial Diets, courts, and other institutions became far more influential or powerful? Could Maximillian's Reichsreforms become more successful?
Also, the Emperor doesn't have to become more powerful in this timeline, merely the imperial-level institutions. A more powerful Emperor wouldnt' hurt, but I want the result to still resemble more of a federalist structure.
TLDR:
- How could the HRE evolve to become more federal rather than confederate?
- I'd love some clarification / corrections on what I posted above about early modern states; it'd help a lot with future writing.