I think what your bringing up is...'is it really safer being 3000 ft farther down the runway, waiting for VR, then if I had just done a max thrust take off' ..the answer is obviously not....
Or...'is it safer to barely get over those obstacles doing a reduced thrust departure, vs get over them faster, higher?'
the answer is obviously not...
Reduced thrust is all about one thing = Stretching out the engine overhauls as far at the mechanic with a boroscope will allow it, and still sleep at night..
And what do the mechanics look at....the blades basically...and reduced thrust departures, will be easier on blades, less sufidation, less pitting.....
but they can't look at bearings...and having had a bearing failure....
Now while others in here are probably tired of me ranting against reduced thrust departures, technically I am not against them...long runways, no obsticles...no problem.......you just have certain airlines that stuff the right seat with 200 hour pay to fly marsh mellows, then plan the accel/stop numbers into the grass, flying overweight, with blind mechanics behind the boroscopes....