Come January, I foresee no change to existing rules at US Airways, other than PT times will be 10 hours in duration instead of 9, and long call callout will be 10 hours (12 if the WOCL rule is triggered) instead of 9. FAR 117 does not preclude the current system - it just says reserve is automatically considered long call unless designated Short or ASB. A Short Call block is just that - designated as Short.
I do think Reserve rules will be a major point of contention in JCBA negotiations since the differences between the US East, US West, and AA contracts are so different. Finding something that captures the best of all 3, and getting the company to consent to it, will be important.
In any case, this isn't like a change in pay rates. You can't throw a switch overnight. You'd better believe that changes to existing reserve practice (for any portion of the pilot group) will be reported well in advance to allow us (and the schedulers) time to wrap our noggins around the new system.