Chinese tech site Expreview.com claims that Jim Keller, one of the AMD's main chip designers is hatching out a new architecture for 2016. This would be separate from the K12/Skybridge x86/ARM hybrid core we already know about.
Keller worked with AMD's Dirk Meyer on the DEC Alpha 64-bit RISC processor, then came to AMD to work on what would be the K7 architecture, more commonly known as the Athlon. He was also involved in the development of the Hyper Transport interface and 64-bit x86 specs, which appeared in the K8 design.
According to Expreview he is working on a new microarchitecture to overcome some of the shortcomings in AMD's Bulldozer. Bulldozer adopted clustered multi-thread (CMT) designs used in the Alpha 21264 microprocessor.
The processor runs one or more dual-core modules that communicate via HyperTransport if there is more than one module (two for quad-core, etc). Each module has two integer cores but one floating point unit, which is shared. Allthis makes Bulldozer less efficient than Intel's chips, which have the FPU in every core.
The word on the street is that Keller will dump the CMT design in favour of a design with simultaneous multi-threading which is what Intel does. AMD for a long time eschewed hyperthreading in favour of upping the number of cores.
Expreview points out that the Athlon FX and Opteron line don't have a roadmap beyond 2015, and Keller's project is set for a late 2015 introduction and ship in 2016.