I've read a theory that the spec was restated because some emissions standards (maybe noise emissions standards?) were tested at the rated "maximum" horsepower.
The engine itself hasn't changed much if any physically, though there may be some software changes to the control computer, besides those obviously required to work with a different transmission. The reports I've heard have not been that the new variant feels less powerful in use; rather, that it works just fine and the new transmission is a definite improvement, which it would also appear to be on paper. The gaps between the upper gears are not so large, so downshifts at highway speeds are not quite such a big production.