Well, just kind of an FYI on this. Using just the tier 2 weapons that can have an elemental and an elemental burst effect on them, the Green Steel Short Sword is *already* going to outdamage your +4 Flame Burst Rapier of Pure Good. Once you get to tier 3 and can potentially add in another damage effect (not sure yet, haven't seen any tier 3 weapons with the damage effects) then the margin is going to get even bigger.
Currently, the short sword would be about 2 - 3 DPS higher than the rapier that you are using.