The renaming scheme isn't as bad as we've seen before: according to the slide, it seems that only the 5700-series would be renamed to 6700-series to support the HD6000 series marketing
AMD seems to have been on the crossroads of which naming scheme to adopt. The first scheme based on conventional logic tells users that Barts-based SKUs should sit in the HD 6700 series, and Cayman-based single-GPU SKUs in the HD 6800; while the second scheme promotes Barts to the HD 6800 series, and Cayman to the HD 6900 series, pushing the low-volume, high-end Antilles (dual-Cayman) graphics card to the HD 6990 SKU. Evidently, AMD chose the newer, second scheme. The only rationale that makes sense is that the x800 series seems to be very popular, and if Barts, with its radically redesigned SIMD components can perform on par or better than the HD 5800 series SKUs, that's enough to justify its upwards push.
Since the new performance SKU will be labeled HD 6800 series, that leaves some vacuum with the HD 6700 series. The solution to this came in the form of a perceptually bad practice of rebranding Juniper-based SKUs to HD 6700 series. There is a possibility of AMD stepping up clock speeds, or adding software features to the HD 6700 series, but that's as far as we can see the Juniper going. "Turks" and "Caicos" are new GPUs, that trail behind in the HD 6600, HD 6500, and HD 6400 Series, respectively.