You know, if you're gonna make a thread about how Wardens are overpowered, at least have the decency to actually read the responses. 2d6+18 is not an accurate comparison here.
As Mengu pointed out:
It's 0.5 points off actuall. I'm comparing at will powers, 2d6+13 (brutal 1) which is 21 average, vs 1d12+14 which is 20.5 average. I say 0.5 points is pretty close.
Now, when you're comparing the Warden in a Guardian form, he gets +6 damage on a hit, which comes out to 27 average damage
on a hit.
The Dwarf Fighter, on the other hand, can use Rain of Steel, which adds 6.5 damage every round, regardless of a hit or miss. So, he'll actually hit for 27 damage (same as the Warden), but also do 6.5 damage per round to any adjacent enemy without needing an attack roll. So in fact, he'll actually outdamage the Warden over the course of the encounter provided that he has multiple enemies around him.
Alternatively, he can use Villain's Menace. Assuming that he hits with the power, that's a +2 to attack (bringing up +3 compared to the Warden, meaning he hits approximately 15% more often) and adding a flat +4 to damage. So while now he's 2.5 damage behind the Warden in Guardian form, he'll probably still outdamage him over time due to the increased accuracy of each of his attacks.
There's also Bedevilling Assault, which is a great 5th level power from Martial Power. Basically, once per round when an ally hits the target the Fighter gets to make a melee basic attack as a free action. This would come out to 1d12+10, which is an average of 16.5 damage every time he hits on the free attack. Assuming a 50% hit rate, this increases his damage against the target to about +8.25/round. Combine it with Villain's Menace and it gets
really nasty because now it's 1d12+14 and he's at a +2 to hit.
Speaking of which, that's one thing that Fighters have over Wardens. A Warden can only use one Guardian form at a time, whereas a Fighter has many powers which aren't stances that can stack certain bonuses. You can freely combine Villain's Menace with Rain of Steel or Bedevilling Assault in a single encounter for a
large spike in damage. Perfect for taking down a BBEG.