Don't be ridiculous. We all know what the most powerful thing in the Diablo universe is:
Powerful heroes can one-shot the most gigantic and powerful of all demons. But doors? Nope, one hit isn't always sufficient, sometimes those nasty obstacles withstand the first impact and demand a second attack.
Experienced characters plow through hordes of monsters like there is no tomorrow. No matter the type, size, or fierceness of enemies: barely in sight of the player, enemies drop to the ground, giving up their precious loot obtained from the siege of Tristram's neighborhoods. Nothing can stop them - except for... doors. I have seen it with my own eyes, witch doctors and necromancers stop their high-paced hunt in front of a simple door, charging up their spells and waiting for magical powers to be ready before continuing their crusade.
Doors are unmatched in their might and power. To settle this debate, I call for an eyewitness from another universe who knows all too well about the power of doors.