I do 330-390 ice lance in fire build with around +980 spelldamage (I have more but all over 980 is Fire only). In frost build with the same spelldamage (~1150, but instead of Fire - Frost) it might be around 700-800 ice lance.

It isnt that hard to gather spelldamage mostly gear. Our spriests and warlocks have got over 1450 spelldamage

personally I go for crit (40.50% raid buffed)