According to the Korean news site ET News, Samsung may stop making chips with Cortex A15 in 2014, and they may be using their own custom CPU cores, just like Qualcomm, Apple, and soon Nvidia, too ("Denver" core in 2015).
To be honest, I was surprised Samsung didn't start doing this earlier, but at the same time, 2014 seems like perfect timing to make a new chip. Why? Because of the brand-new 64 bit ARMv8 architecture, and 2014 is the year we'll start seeing the first 64 bit ARMv8 chips, whether that's from Samsung, Qualcomm or ARM (Cortex A57/A53). So it makes a lot of sense for Samsung to have waited until they could build a new chip directly on this platform.
Apparently Samsung wants to optimize the bus performance between the CPU and memories such as RAM and NAND flash. Samsung has also been developing the open source Flash-Friendly File System (F2FS) that should significantly improve the speed for flash memories compared to the current ext4 file system. This file system should be supported in KLP this fall, if Google adopts the 3.8 kernel (and they probably will), which also includes support for the ARMv8 architecture, along with other optimizations.
It's probably not going to be a big.Little chip anymore, but more like a Qualcomm one, where it only uses 4 cores, but are more efficient. Samsung has had quite a few issues with the big.Little architecture and the drivers for it, because it seems to need a lot of optimization to achieve its true potential.
Another reason Samsung may want to make its own 64 bit is because just like Nvidia and Qualcomm, they're probably interested in entering the server market, as the ARM server chip market is poised to explode beginning next year.
Ultimately, I think it's a very good idea for Samsung to make its own ARM-based CPU, and maybe even a GPU in the future, although for now they'll probably continue to use ARM's Mali GPU, or if Nvidia is smart, they can convince them to use their own Kepler/Maxwell GPU, which might be more powerful than Mali alternatives in the future.
More competition like this is welcome in the ARM space, and it proves that the ARM ecosystem has much more competition than the x86 one ever had, which means we'll keep getting much faster and much more efficient chips every year at the same low prices.