777 Wing
As I understand, the B777 was Boeing's first aircraft designed with computers. As such, they believe they created a wing with an eliptical lift distribution (which produces the least induced drag) using varying cross-section and washout, and hence no need to use winglets (which reduce induced drag).
All airliners use supercritcal wings nowadays to give low drag in the transonic region by keeping the shockwave as far back as possible on the upper surface. This is done by keeping the upper surface relativelyt flat so that the air is not accelerated. As a result, the coefficient of lift is reduced (due to not much camber). To overcome this, the rear part of the wing has a cusp to regain some of the lift lost.
EPR
EPR or Engine Pressure Ratio is defined as the Jet Pipe Exhaust Pressure / Compressor Inlet Pressure. As the area over which the 2 pressures act is unlikely to change with engine life (Thrust = Pressure x Area), the same EPR should give the same thrust despite age. The older engine is likely to need more fuel and will run at a higher EGT as it will be less efficient.