Happy to kill the idea of touchscreen Macs for the umpteenth time.
But no ARM is a bit of a surprise. It would ensure Apple had complete control over their own hardware and software. An ecosystem with their own hardware pipelines, so they're not reliant on third parties. Perfect OS optimisation. Plus MS are releasing W10 for ARM chips (rumour has it they've compiled a pretty efficient x86 emulation) so it wouldn't exactly be a step back.
Again, surprising, but they possibly don't want to offend Intel if they're looking for new chips.
<crazy "I called it here first conspiracy"> Possibly Apple & MS are quietly in cahoots about migrating to ARM and then will release everything within weeks of each other, chopping off Intel for their own hardware lines without prior warning. Surface Pros with Apple A-series chips.