Gort said:
To be honest, if you look at the amount of damage a 4th ed wizard deals out (in my playtests, anyway) rather than the number of monsters he gets the "kill shot" on, he stacks up extremely well against the other classes.
D6+5 damage against up to 9 targets averages between 8.5 and 76.5 damage a round, as at at-will ability.
Compared to the fighter, who does an average of 14.5 damage with his cleave, assuming the enemies are set up right, the wizard is still an extreme damage dealer, in the right situations.
Well, I was refering to 3.x mechanics, since we've them those in play across a broad range of levels. So far AoE damage in 4e does seem more valuable.
However, I don't value AoE damage that highly in principle. Lightly wounding 9 enemies can do vast amounts of damage and be completely worthless at the same time. Basically, 9 singed enemies take 9 attacks on their turn. Spreading out damage that doesn't kill enemies means that they're still alive, they still take actions, and they're still doing damage to your team.
Let's say we have two teams of five fighting - like the example 4e characters, HP are basically 20-30. Doing 30 damage to one guy with a spell seems like a vastly better option that hitting each foe for 6 points, since you're taking out one enemy and likely disrupting the plans of the other characters.
Granted, that example is quite extreme. Area damage generally isn't priced the same as single target damage (actually, in systems based on DR type defenses, AE damage can actually be more expensive per total point.

)But I think it illustrates the point that equal amounts of damage are not necessarily of equal value, so multiplying damage per guy times the number of targets isn't always a good way to gauge impact.
Similarly, overkill damage doesn't matter either, which can often make single target spiking wasteful. Of course, when you look at a larger group context, things get really interesting:
Consider we have a monster with 40 HP. Our fighter hits for 20 damage, so he kills it in 2 rounds. Our wizard has a blast that does 15 damage. Let's say the fighter wins initiative and does his 20 dmg. The wizard then blasts the monster for 15. OOPS. The fighter will automatically kill the monster on his next turn regardless of what the wizard does. The wizard's 15 attack did not affect the time that it takes the enemy to die in any way, so the actual impact of his attack was zero damage. (Or we could switch the damage and placing for the wizard and the fighter to make the sword swinger irrelevant.) Again, this case was highly simplified as the characters were doing automatic, non variable amounts of damage.
But the point is that the value of damage depends highly on the way its dealt and the situation. Prioritizing total damage over impact can be a huge a mistake.