Cortex-A15 designs and up already offer 36 to 40 bits of addressable memory, or from 64GB to 1TB. This is at the OS level, of course, so individual 32-bit processes would still be limited to 2-3GB without intentional PAE, but that's hardly a limit in a mobile design.

But ultimately it isn't about memory in the near-term. ARMv8 offers more, larger registers, instructions, a higher hardware baseline, and in the future higher memory.