The intrepid minds over at Wowhead have been busy datamining as much of the new 5.2 PTR as they can, and they found the models for the next round of tier gear. While tier 15 doesn't appear to have names just yet, the models are pretty representative of what will likely be a very primitive-feeling raid, with animal and tribal themes throughout. The looks are incredibly detailed, iconic, and honestly I think as far as the rogue set is concerned, this is one that I'm not going to transmog over.
Tier 15 also seems to have some of the most interesting belt designs I've seen in a long time. Some of the sets have belt buckles that are even animated with sparks and other oddities. While not all of the tier sets are complete and available for viewing, each has at least a few pieces that you can check out if you're so inclined. Take a look at Wowhead's post
for still images and 3D models of each of the different tier sets.