There will not be a monumental shift in a cost structure (both pilot pay and fee-per-departure) or else it may be the end of the regionals.
My guess is it will contribute in a big way to changing what a 'regional' airline is. Regionals started life with AC of 19 seats and smaller. As the fleets of J31s and B1900s were parked they replaced them with larger turboprops like Saabs, Brasilias and Dash 8s. Eventually even those AC became uneconomic partly due to all the FAA rule changes - all AC must have TCAS, the average pax/bag weights have increased to the point you can't carry 34 pax, the GC envelopes have been curtailed, etc. For years the FAA has been increasing the 'cost structure' of regionals to the point the FAA has changed the business significantly. Look at the abandoned terminal in PIT that was built for turboprops. 50 seat RJs are already on the same road. Between increased fuel costs, pay increases from labor agreements and labor cost increases from the new rest rules 50 seat AC aren't looking very profitable. In a few years 'regionals' will have very close to the same cost structure as 'mainline' carriers and operate mostly 70 seat and larger AC. The only positive sign I see ahead is that as the fleets of 50 seat AC are parked hiring from retirements should start again at the 'majors'.
Most regionals use computer 'pairing genarators' for pairing construction. These programs have user defined entries for maximum duty day, min rest, duty rigs, trip rigs, etc that will come close to simulating the rumoured proposal. If you want to know the impact on your schedule of all this ask your management. If they are any good at all at their jobs they have already tested it and know the answer. And they more than likely do not want to share with you because in most cases you will not like the answer.