Because the Super Pershing needs Armour and the gun from the M56 Scorpion. Stats being .36 accuracy, 220 pen, 240 damage and 2.2 aimtime.
Like the CDC it would be nice if it had 2-3 qualities to make it better. CDC has great gun and mobility, with poor armour.
I believe the Super P should have great frontal armour again with a good gun, because it has worse than Heavy Tank mobility.
Thx,
Capt Canada