Vaibronco,
Of course we refer to instruments to make sure we are on the profile for Cat A takeoffs. But I disagree that external cues are not utilised, and if anyone is teaching this, they should not be.
It is in fact essential that the pilot flying is looking outside during the takeoff, because the chances of a successful reject are severely diminished if he is not looking out. It is also during the initial stages of the departure that collision avoidance by means of lookout is most critical. There are more foreign objects, birds, wires, tv masts etc below 200 ft than there are above.
If there are 2 crew, then the pilot monitoring should be assisting by looking inside and ensuring that the departure is according to the profile.