Can't Deidara C3 (or is it C4?) the meteor while Nagato also uses a CST to counter it? And while Madara's regenerating, Itachi speed blitzes + Totsuka's.
if the meteor is destroyed he wont need to regenerate also akatsuki will be in the line of fire when deidara is using c4 or c0 edo madara wins low -med diff