(c) improved obstacle clearance - not for close-in obstacles (straight away they are compromised by the net flight path's being lower initially due to the longer TOD - however, once the overspeed NFP intersects the min V2 NPF, the obstacle profile is enhanced (read either improved clearances or add some weight to reduce the sums back to minimum requirements).
Indeed so.
Runway 16 at ZRH is a prime example.
With both the B707 and the L1011, improved climb (or, as it was known then on the 'ole 707...overspeed takeoff) allowed for enhanced payload, for long range ops.
OTOH, BOM runway 14 was not long enough, and besides the obstacle was too close in....however, an emergency turn was available for OEI...left, to avoid the granite.
Improved climb procedure has been in use for
many years, with positive success.
IE: nothing new.
Just another tool in the toolbox.