Better firepower, Strong armour (with side armour), Lighter, Fast Mobility, Easy Production, With Clear Radio for communication, uses cheap gasoline, better ergonomics, special tracks for dirt snow sand etc, better shells, better optics and vision, two machine guns, with a flamethrower on the front, an engine that has more horsepower and not a loud engine, can be used for amphibious operations,
Those are my tank suggestions.