As I understand it, reverse thrust is not considered when detrmining performance for regulatory purposes - so if available it is a bonus. However, if used properly and in conjunction with the other stopping aids (correct training!)then it will shorten the stopping distance. However, if not used properly it may be a distraction or even contribute to directional control problems. advice - learn the correct technique for YOUR aeroplane.
As for the point on tyre flex - the brakes create x amount of heat when stopping a particular aeroplane from a particular speed at a p[articular weight. So, if you stop quickly, you will create the same amount of heat from the brakes but the fewre number of tyre rotations will create less heat through flexing.
In my experience of training pilots, most are under the impression that they have applied full braking when in fact they are only applying 1/2 to 2/3 braking effort. they are amlost always surprised at how hard you have to press to stop. So, if you have autobrake with an RTO setting - let them do it. If not - push like your life depends upon it (which it may).
As an aside, the motor manufactures are finding the same problem - people drive into an accident with only partial braking applied. This is why we now have Emergency Brake Assist which increases braking effort if you keep the pedal pressed for a certain period of time. The computer assumes that you MEANT to do an emergency stop, even if you actually are not! RTO setting equivalent?