I'm an old school TWer. I consider Blitzing to be the TW equivalent of playing FIFA on "easy" with all the cheats, and then going "look, I won 88-0!"
I play with my own set of Iron Man rules - never break an alliance, always go to an allies aid, no reloads etc.
As for the Blitzkrieg itself - that can still be done. Indeed, part of the fun of turtling is to suddenly unleash an all-powerful army on the enemy and lay waste to their lands before they know whats happening ~:) . Took me forever though playing as Bactria to win my RTRPE game - I promised myself Rome would be the last settlement I took to win the game and capture my last objective and 50th settlement. I furthermore promised myself I would do it with elephants in my army. Do you have any idea how long it takes to get Elephants from India to Rome...?