This latest batch of schedule changes brought good news. An upcoming flight was changed so that it leaves 2 minutes later than before. A previously illegal connection just became legal.
Net result is that we can get from LHR to home on the same day instead of overnighting in DFW. I called EXP desk and explained how I would have surely booked that connection if it had been available back when I bought the tickets. EXP desk saw the logic. Now we're confirmed on last flight home of the evening, instead of first flight the next morning.