V2 flaps zero is going to be a MUCH lower speed than Venr. Decreasing pitch attitude to accelerate to Venr from V2 should be done at the computed acceleration altitude. Doing so sooner will invalidate the climb gradient/obstacle clearance calculated during the performance planning process, so why do it sooner? The calculated departure path meets climb/obstacle requirements only if the profile is flown as planned. The obstacle clearance plane doesn't change just because one can see the terrain visually.