"manifest"
when i was in the back seat and then the right seat of a three man aircraft, i made it a point to learn from every flightcrew's reaction to every event we encountered. one very good captain, now with atlas cargo, had a philosopy of waiting til the possible malfunction would "manifest itself"
yes we are to use our hopefully indepth systems knowledge and wide read knowledge of all the aviation incidents/accidents/causes-effects-results to our individual minds' abilities to imagine all the possible ramifications of any malfunction that we experience. but to let our imagination go free range without any manifest evidence is not any safer that a conscientious continuation of the flight as planned until some other "damage" does clearly display itself.
i don't know the route taken, but if the captain proceeded knowing that there were alternate airports with sufficient runways and services to deal with whatever might come up, and basically using the fuel to produce distance while reducing the weight in case a landing was needed, there is nothing unsafe about that.
perhaps he/she did consider all the possible reduced stopping capability-possible flap/hydraulic and other second stage effects all along the route and especially at the proposed destination. being delta i would be very surprized if they did not communicate with ground mx-operations-maybe even other pilots on the company frequency and get second, third opinions. i would. perhaps he/she configured early on the approach, cautiously watching each flap and gear event and feeling of the aircraft flight controls. very few things can happen to reduce safety that will not make some manifest display of one sort of the other if carefully observed.
he/she was there, not i and the lack of significant event is evidence enough that the correct thought process was followed and executed.