Just say no to Caster Weapons.

Enhancement Shamans in WotLK
We view Enhancement as a melee class that should be wearing melee gear. However, one of the interesting things about the shaman is throwing out some spells with that melee too.

Our view of things is that some smart theorycrafters started wondering if using two fast caster weapons with two flametongue enchants would end up being the right way to go. The way the discussion sort of ended up was "maybe, but it might be close" but a lot of the community took that as a mandate. Or maybe they were just shocked by the supposition because it felt wrong for a melee class. We agree it feels wrong, so we're doing some tweaks to make it even less likely to be the most optimal set up. If you are saving up badges or arena points or whatever for your enhancement shammy, I would definitely NOT go out and get two fast caster weapons. (Source)