When I was flying KC-135s we practiced at the instructors' school doing single engine approaches and go arounds. And the J57s put out only a pathetic 13,000lbs of thrust and we considered the airplane 'light' when we had only 40-50k of fuel on board for a gross weight of 160k.
Yes, it was touchy and you had to pay attention and anticipate the increased drag with extending gear and flaps but one could hold level flight with gear retracted and flaps at 30deg.
And in the 727s, the concern was that once you lost a hyd system due to an engine being lost you could not retract the gear or flaps so that became a major concern.