In terms of pushing the envelope, the KC-135 maneuver in the video was routine, while the B-52 crash was the result of flying at and, unfortunately, beyond the margin.
The tanker was doing a "landing attitude demo" variation, a maneuver taught at instructor pilot school, albeit with gear down, along with 90 degree bank refueling with a B-52 on the boom, and used to show new pilots the visual landing cues. It was no big deal, although visually impressive.
Another cool variation of the landing attitude demo is the "elephant walk", in which reducing and adding thrust alternately on outboard engines causes the left and right main gear trucks to touch and rise, seeming to walk down the runway. With a little practise you can get five or six steps on a 10,000' strip. This maneuver, too, is routine.