I think Transmog could definitely be expanded in a few ways. For one, I think it would be nice if it also allowed us to recolor gear how we want. This would be huge for customization. I also think that Legendary items should be possible to transmog. I understand the reason they haven't been, however, the way it is now legendary items just sit in your bag / bank and that isn't really epic at all. With transmog people could actually use them.