well i started to read this and was astounded that so many think the hare would crush the turtle, i am a turtle but after 10ish turns my nation controls the strategic provinces i need for
A income
B defense
C expansion of military forces
be advised this does change with every nation, you cant go after bruges and antwerp as the italians, you cant take adana and antioch if you are danish

dont think that the turtle gets that slow a start, if done right any faction can have the best economy in a few turns, and that directly translates into spending power eother with mercs or buildings to recruit an army that is professional. honestly i would like to see a hare go up against a eastern european army commanded correctly. tho if it is western europeans it is a different story you are almost forced to fight on the hares terms unless you are scotland or england (navy).
now to address the miltia aspect of blitzing, that is easy to address, chop the armies head off then push through minimal losses max casualties. it doesnt matter if you swarm with militia if you can kill the general, they are still gonna rout.
Fisherking good point about alexander and attila, but to counter that GENGISH KAHN is all you really have to say.
in some of my long campaigns i have been the hare and sure you win very fast, but your dread skyrockets and under most scenarios you would simply lose against a human player, because if you are gonna play a battle map game there will be 3+ players and you cant leave a flank open to rush a faction because only a fool would stand by and not go for your key provinces and ports.
also to throw my last idea out there. imagine you are a blitzer and come up against a entrenched army of either faction specific early units or a professional army you can either
A. go around but then open yourself up to a pillage campaign by a human enemy
B. try to go threw them but that would result in a serious loss of manpower for your side and you could not possibly get threw in one turn, which would allow me to divert all my economic resources (the ones i built up) to create yet another army and brush your battered and tired militia/merc army to the side and then advance on the next defensive postion to once again frustrate the blight out of you. this would go on and on and on until the war of attrition went to the one with the most developed core provinces and the most developed front line castles.
C. bribe me, but that just wouldnt work cus i would never put a army with a disloyal commander

also i would like to say, askthepizzaguy you do have some very good points on why the hare would win