If you roll an area effect and make different attacks vs. multiple targets, but only one damage roll, and roll minimum damage, but critically hit one of the targets, does that target still take maximum damage?
Actually, it is the same way it has always been. Area effects were always a set amount of damage, and then a roll for a saving throw.
When they changed saves to defenses, you still have a set amount of damage and a roll to see if or how effective it is. It's just that the attacker is now making the roll instead of the defender.
The only real change is that now a crit maximizes the damage.