The 458 is a COMPLETELY new car that Ferrari added to their lineup... the 997.2 is just a small model refresh made just to keep the market from dying until the 998/991 Turbo models are released. You can't expect huge weight savings and more than 70bhp added on for just a simple 997.2 refresh.

As for the wet/dry sump arguments, you have to remember probably 85-90% of the Turbo customers are lawyers, doctors, CEO's, etc. Not all of those people are the hardcore tuners or "enthusiasts" you see on this board. You have to remember Porsche has to please the general market, and a 20hp boost with slightly less weight and emissions look good to those types of customers. They probably made the change because in the long run it may save them money due to the recent sales decline with the economy... or something along those lines. There's always a reason...