Speaking from long experience with modern turbines:
Windmilling is a non-issue. Short of oil starvation, you can fly with one shut down until you run the tanks dry, and bearings/seals/pumps will suffer no harm.
And derated and/or reduced-thrust ops are so universally standard that they form the very foundation for the very safe & economical airline industry. Pprune seems to attract a few trolls who have never earned airline stripes, and they profess to have a better plan - but their engines get yanked many times more often than the airlines' engines. Hot rodding is just fine, but don't expect the airline pax to subsidize all that noise!