The problem with it is that Water/Dragon lacks many resistances. It has 1 weakness, sure, but it also has 3 resistances. One of which being Steel... Dragon and Water cancel most of each other's weaknesses AND resistances.
I mean, double resistance to Water and Fire and only 1 weakness are still nice, but not the best.
"Combine Cloak and Dagger with Boots of Swiftness so CC doesn't stop you from moving faster toward defeat." - Frost_shock_FTW