Imo, Frostbreath is not really viable as an endgame weapon since both its base aps and dps blow
not discounting the possibility it might in someway be used end-game (by others) that is not really my intent here, it is for the levels between 50 - 58 and then to tinker with properties to see how it might be used. Soul Taker is a different range and at higher levels I'm either using a shield or staff with a Templar. I think there is probably a method to extricate and utilise the chilled damage property somewhat apart from the weapon itself but I'm not quite sure how, and without finally looking at mechanics (which I really should by now, as a rule I try to avoid too much numbering in games) I'm not too sure. At a guess additional multipliers then being doubled could effectively work (which reminds me I don't need the gems in the unique !), and something along the lines of Heavy Strike, the gems (assuming they will work together) which produce a chance of double Heavy Strike damage, melee splash, concentrated effect and then the effect of the unique. But the problem with this method is that is primarily working on the base damage of the weapon and this is where I think any method that really makes the use of this unique should try to externalise the overall effect - and without deliberation I'm not too sure how to go about that.
yet the more I think about it however it seems as though it would be necessary to have the chilled (Frozen ?) effect in advance, two or more attacks would make the effect redundant with many other readily available tradeable items having better overall dps. I gather the method is to somehow separate damage from weapon functions and so on