Here are my 2 cents on this matter: I have been involved racing for the last 30 years so I think I have a realistic perspective on this.
Modern shifting is a distinct advantage in competition; particularly in the big bunch finishes.
In time trailing the aerodynamic stuff matters if the athlete is capable of riding in the neighborhood of 1 hour (for 40 km).
In hilly races I think it helps significantly if you can take a few pounds off the bike.
I don't think the other technical improvements matter too much.
In serious competition I can take or leave the lugs but I want my STI.
Jamie Swan - Northport, N.Y.