The smack in the face by Sony when PoP came out was this nice and easily obtainable weapon for a rogue to have a proc that would blow escape has finally been reconciled.
I don't see any reason that people are complaining about this but when I used the original shank, you could proc it all day long but you still ended up with a dot. Now with a direct damage spell, you get the entire effect of the proc since it does not need the additional time to wear off nor will it be resisted by darn near everything that is even remotely resistant to fire damage!
Unresistable damage is hard to argue over a 50/tick dot.