A number of AoE attacks do rather low damage due to the fact that they are AoEs, while this is understandable... I do believe there is a better option to this...
Take a look at a number of Ranged AoEs for an example of this better option... they do a large amount of damage to their primary target and less damage to subsequent targets caught in the blast radius... This is a good model for AoE attacks.
However, if you move to melee, PBAoEs, or many of the remaining ranged AoEs you'll notice a completely different model... instead of dealing significant damage to one target and less to the rest they do low damage to all targets...
I propose this be changed... nearly all AoEs should do higher damage to their primary target... there honestly are very few AoEs where this is impractical (Flash Fire, Pyre, Force Eruption... and similar AoEs, I'm looking at you)
For example... Melee AoEs should deal damage along the lines of the following model:
(Note: Numbers are for example use only, and are not representative of actual damage values in any way)
Dealing significant damage to one target while dealing a lower amount to the rest.
As for the powers mentioned earlier where such a system may not be viable or logical, & the majority of PBAoEs, another option still exists (and is actually in use on a couple existing powers even) for them. The closer to the center of the AoE the target is the more damage they take.
so it would look something like this:
(Example is a 15ft Sphere)
Center of AoE: 1000 damage
3-6 ft: 800
6-9 ft: 600
9-12 ft: 400
Edge of AoE: 200 damage
The actual numbers should still remain lower than a Single Target attack on the primary target but not so low that AoE powers are insignificant against single targets.