http://www.electronicsweekly.com/Articles/2010/09/09/49414/Update-ARM-Cortex-A15.htm
Word is that there's a move to a triple-issue front end, 128-bit floating point NEON, and improvements in the memory hierarchy (more than one load or store at a time would be quite nice). Stated goal is a typical 50% better IPC over Cortex-A9.
If this really does ship in 2013 then I hope Intel has moved on from Atom by then, or else they don't stand a chance.
ARM is obviously gunning for servers here too, and if their perf/watt at 2.5GHz really is competitive vs Intel and AMD then they might stand some shot. PAE is kind of a dodgy way to get more memory, but maybe if they did it right they could get enough access to more memory without hurting performance too much... When you think about it, full-on 64bit is kind of a waste for most of what it's good for, when just moving to say 40-48bit AGUs and wider address buses would accomplish a lot of the same thing... with enough ISA tweaks.