I don't know much about Pyrebrand. I've heard it was strong before the nerf but I wasn't about to spend a week straight trying to farm it. Especially when I knew it was instantly going to get kicked to the curb.

Way of Fire is okay enough as a little bit of extra burst. Useful if you want to layer many instances of damage since it acts like another strong weapon enchant with a much shorter cooldown. Or you can also think of it as a very strong DoT. It will beat out the damage of almost all other skill-based DoTs, which really isn't saying much anyway. Either way you aren't going to notice it much against well equipped players with a solid defense strategy. It felt to me like scribing pretty much superseded this set in terms of raw damage potential. DoTs are not a prerequisite by the way. You can just as easily use a spammable or even just light attacks.

You could also use Poisonous Serpent since it basically does the same thing in terms of damage. But you'll need to be able to land those light and heavy attacks very consistently which... is hard when the server hamster is having heart attack. You will also have to make sure you have some kind of poison effect on them but that's not super hard as a DK.