I drive a Falcon 2000, which has FADEC. No provision for derated TOs. It's quite nice never seeing the departure end of the runway before rotation.
But.
If Boeing and my employer (notwithstanding the compromised nature of every rulemaking enterprise) tell me that a de-rate is OK with them, it's OK with me--provided that the assumptions and conditions match.
Seems to me that all of the risk in a de-rate TO is in the accelerate-go scenario. I presume that if an engine fails etc. you shove the levers to max (or it does so automatically) and you make your OEI climb gradient.
Have I got it wrong?