No. Not if they want to launch this year. Don't listen to anyone who says otherwise because they are clinging to false hopes. The fact is changing either the type of memory, or increasing the amount of embedded memory is an incredibly significant change to the silicon. It means rolling back a number of steps in a very long process required for designing, testing and retesting chip designs. Not to mention much of the software stack and dev environment (and games) are currently built around the current paradigm of DDR3, ESRAM and DMEs. Changing any one of those will have repercussions to the whole system, OS, drivers, APIs.
The only thing that is remotely plausible would be an increase of the main memory to 16GB, but that much RAM that is that slow would be incredibly wasteful for games. They'd probably end up locking off half the memory for system use anyway for way more multitasking than is really necessary.