But the starting point were the performance of the French and Prussian artillery in 1813-15, so some of your arguments miss a little bit the point.
The most damning critc of the OLD Prussian artillery I have found in "Die Schlachten und Hauptgefechte des siebenjährigen Krieges" (1837) by the Prussian artillery officer Decker, despite its title the introduction of the books covers also some developements during the decades after the SYW and is relevant for our discussion. He brings most of your arguments for/against the Prussin artillery, the major obstacle in Decker's opinion was indeed the Große König, "der sich an der preußischen Artillerie versündigt hat".
On the other hand, he also rates the (pre-napoleonic) artillery systems of Austria, Russia and France and is not impressed by the French system: "better any system (France) than no system at all (Prussia)". Decker admires the Russians, because in their army the artillery became an equal branch much earlier than in other western European armies; the Austrians, because their Liechtenstein system was in Deckers opinion well worked out and a real improvement.
(BTW, on page 11 he also describes the use of a "starken Taues", which he calles Prolonge for the movemnet of the heavy guns on the battlefield during the SYW:-) )
This book is available on Google.
Greetings from Graz