I read a lot about the differences in tactics and military technology between WWI and WWII; that WWI was a war fought with 20th century weapons but 19th century tactics, that WWII was about speed, blitzkrieg etc. I guess what I'm interested to know is who among the Allies and Axis were the ones who revolutionized the military leadership side of things, and how did they go about doing it? Were the lessons learned by the end of WWI, or did they come about later? Were the ideas inevitable given the new technologies, or were there genuine military thought innovators?
EDIT: I meant better during WWII than WWI. Sorry bout that
Competency is abstract and therefore very difficult to measure. Plus, leadership is present at every level of the military hierarchy. A general and a corporal both lead, just in different ways. So your question is so broad its almost unanswerable.
It seems to me like you're interested in tactical and operational innovation between 1914 to 1939 and how lessons learned changed military thought and practice during that time period. Correct?
WWI was a war fought with 20th century weapons but 19th century tactics
This is a false supposition to start with. It may be accurate to say that some of the combatants used some 19th century tactics at the start of the war, but these tatics changed and rapidly evolved as the war went on.
The technological changes that occured in WWI are staggering. Although some innovations were used in previous wars, this was the first wide-scale conflict in which combatants on both sides had access to rapid firing recuperating artillery, barbed wire, machine guns, and magazine fed rifles using smokless powder. The war saw the introduction of chemical warfare, aerial warfare, tanks, submarines, motorised infantry, squad-level automatic weapons, predicted indirect artillery fire, creeping barrages, indirect machinegun fire, mines, torpedoes, dreadnought battleships and the aircraft carrier.
Tactics evolved to suit. See this link
https://archive.org/details/instructionsfort00washrich note this is a British manual reprinted in the US
Where fire and manouvre tactics are being laid down in official documents in 1917.
By 1918, armies were using shock troops, infiltration, "peaceful penetration", and fighting with carefully coordinated combined arms tactics.
Between the wars, the British continued to pioneer armoured warfare (British theorists like Fuller and Liddel-Hart were influential and the British did experiment with a mobile armoured force) but lost the lead due to spending constraints. The Germans, and in particular Heinz Guderian, studied the British experiments with armoured warfare and drew the overwhelmingly correct conclusions, designing the wermacht for modern, mobile armoured warfare.
While it is fair to say that the British and French lagged behind the Germans in their conceptualisation of modern warfare, its important to point out the the entire British army was motorised by 1939 wheras the vast majority of the German army was still horse-drawn. Furthermore officers like Percy Hobart ensured that the British had a well trained and well equipped armoured force in Egypt by 1940.
Also, land war is only part of the equation. The axis were never able to maintain any form of naval superiority (though they did breifly have naval supremacy in the Med'), nor were they able to maintain air superiority over the western allies. In fact, the axis lost the war in the sea and on the air long before they lost the war overall.
Additional sources Blitzkreig - Len Deighton Fighter - Len Deighton White Heat - John Terraine The Great Tank Scandal - David Fletcher Castles of Steel - Robert K. Massie Achtung Panzer - Heinz Guderian