A design similar to that would be really cool and as Ravin' Ray said, play up his deal with Mephisto. The team could do with a good magic type of villain and I think Diablo could be positioned as that.
I think Wednesday will just be about promoting issue 6 that will be out then. It's probably just going to be the next two days where we'll get news. I hope its revealing merchandise and announcing a FF related book.