Tanks would be a useful piece of hardware if you could protect them from drones and anti-tank missiles, perhaps some type of directed energy weapon or close in weapons system, otherwise tanks appear to be just large moving targets easily taken out by newer cheaper weapons.
You have to reduce their ground direct fire profile by making them flatter. However by doing so you make them more vulnerable to a top attack from a drone, helicopter or guided artillery munitions. You give the enemy a large flat surface to attack. Interesting design problem!