Level 4 & 8 Calomel weapons are terrible. Dragon bane is almost entirely useless at these levels, and 1d4 tidal damage is far from competitive with either random loot or crafted items.
I suggest augmenting the (lesser) dragon bane with reptilian bane (level 4) and greater reptilian bane (level 8). This is still within the same vein flavor-wise (dragons... reptiles...), but is much more useful. These items might then begin to serve an actual purpose.