Well, no, because neither the resistance nor the vulnerability is "canceled".It would be fine if they left off the last clause of the last sentence which is just nonsense. Both the resistance and the vulnerability are applied (and thus one can cancel out the other).
Yup, surging flame sucks, and you'd have to be an idiot to ever use it UNLESS you had a plenitude of attacks that have two elements that include fire (ie fire + frost) AND a way of giving fire resist to your foes that had a minimal opportunity cost.
Basically: either you don't know whether the foes you face will have fire resistance, so the feat isn't worth having, OR you know that your foes will have fire resistance and you're stupid for having fire-dealing powers.
Isn't the point of Surging Flame to make your endless list of fire powers viable when you meet fire resistant foes? If you've got a nice flavor thing going Surging Flame lets you stick to it instead of breaking out some cold powers (and thereby going off theme).
It might also be a nice feat to pick up for a level during the fire themed adventure, then training out of when you move on. In that case the "situation" it applies in might be an entire level's worth of adventuring.
PS
Says who? Not according to the FAQ.There are many reasons why resistance and vulnerability don't cancel each others.
1. Resistance is applied first. If the damage is reduced to 0, vulnerable won't do anything.
I have read and re-read that. Its weird, how can you apply by vuln and res and NOT have them cancel each other? Now Im just confused!
Well, yes. But no.Looking at the MM faq, seems like I was wrong about point 1. Vulnerability and resistance are both applied, basically "cancelling" each other.
They still have the trait "Resist Fire", it just happens to have a value of "0". It is the same as with Vulnerable 5, Resist 5 - the damage suffered by the creature does not change, but the creature still has both traits.