So the 'Great War' against the dead was basically a plot device to weaken Khaleesi's army...
The way things have played out, the 'Great War' now just looks like a plot device to weaken Khaleesi's army and make Cersei a formidable opponent
Before the War, Khaleesi would have destroyed Cersei 's stronghold within a day :
Dothraki + Dragons + Unsullied etc etc etc V/S a paid-to-fight army and NO ELEPHANTS