Completely wrong. It's been theorycrafted and M6/fire EA does comparable damage to the Wizard. So it's defenitely an option - on paper.
The issue stands because the amount of dots generated by the spec is insane. And dots are the cause of huge lag - not an issue for lower levels but definitely bad for higher ones.
You can try and see where it brings, but the damage is there. However if you aim for #1, maybe a Wizard will net you better chances.