Methods are provided for improving performance of a gas turbine engine comprising a component having a rotor mounted in a rotor casing and having rotor blades. A tip sweep is applied to a leading edge of one or more rotor blades each having a pressure sidewall and a circumferentially opposing suction sidewall extending in a radial direction between a root and a tip and in an axial direction between the leading edge and a trailing edge. One or more blade geometric design parameters are adjusted. A rotor casing treatment is applied to the rotor casing over at least one of the one or more rotor blades. The applying and adjusting steps are performed during design of the rotor and cause a measured stall margin to substantially match a required stall margin with an increase in efficiency of the component.