So another updated loot list and another look at that Spellcaster Mace. Its still one handed, although the weapon damage has been toned down. Even with that, if it sticks with being one handed that is 3684 spellpower with a nice chunk of mastery and a bit of spell hit.
I'm no theorycrafter but how could that not be BiS if it actually goes live?
/Discuss
Edit: This is for Enhancement by the way...