Unless the old and new car were tested side-by-side, it's tough to just look at the numbers and say one is better than the other. So many variables that can impact performance can vary day-to-day and location-to-location.
I'm surprised none of the publications seem to have tested a 2014 and a 2015 at the same time to get a better comparison.
Current: 2014 V6 Mustang Premium, Automatic Transmission, Oxford White, Safety & Security Package.
Previous: 2006 Chevrolet Cobalt LS, bone-stock except for automatic transmission.