There was an accident a few years ago (Chicago? DC10? not sure) where the engine failed on departure due to damage to the aircraft (think it hit something, not sure memory a bit hazy). The flaps and slats were damaged too. In reducing to V2, control was lost of the aircraft and it crashed, the reason being that the wings were not the same shape anymore. Maintaining the speed they had would probably have meant the aircraft could still fly. I think this is one of the reasons for changing the procedure to maintain current speed.
Also, in reducing to V2, if you inadvertently go a bit slower you are very close to losing control even in a perfect aeroplane - maintaining the speed you have maintains control and gives an extra margin.