flight directors on takeoff have to be "looked through" in many situations..while V2+15 is the optimum climb speed for most swept-wing aircraft while still in the take-off config...if i lost an engine at V1 i would climb at V2...if i had already accelerated to V2+15..then maintain that speed unless collision with an obstacle is iminent...the dc-10 crew proved a an old adage "ifit ain't broke don't fix it" to be true the airplane was climbing, and had no obstacle..but ingrained procedures instead of old-fashioned airmanship prevailed, and the and aircraft control was lost...the crew had no way of knowing the configuration of their wing..in the few short seconds they had to make the decision that we have had years to second guess...i personally would climb at a slightly higher speed than V2 if a violent engine "event" had occurred, and the aircraft was climbing at an acceptable rate...