The MD-11 suffered from a very high profile accident in the form of the SwissAir crash in Nova Scotia. Unfortunately for this aircraft, the culprit seemed to be capton wireing insulation related to the video entertainment system. After this was determined, this capton was also found in numerous other MD, Boeing and Airbus aircraft with signs of fraying and small fires. It just happened to the MD-11 where this problem first manifested itself.
The Mandarin crash in Hong Kong was purely pilot error in that they were attempting to land the aircraft in a cross-wind condition that was far more severe than the operating limitations of the aircraft. The Newark FedEx accident was attributed to both pilot error and possibly the unreported hard landing that may have cracked the spar.
Although initial performance specifications were not met, these issues were resolved in the early production models and the MD-11 went on to serve as the very long range aircraft that it is today, flying some of the longest haul sectors in the world.
What may have killed the MD-11 was the advent of the big twin jets like the 777 and A330. Although the MD-11 went into service years before either of the big twins, its time was limited by advances in twin jet technology and the move away from the tri-jet. The MD-11 offered the most advanced flight deck of its time which still hangs right in there with the 777, 747 and other modern 2-place glass flight decks. The other factor that sealed the coffin for the MD-11 was the Boeing MD merger which effectively lay MD to rest, along with its product line which Boeing did NOT market or ever intend to keep building. Despite the fact that the MD-11 was the only new build freighter in its class and represented the most efficient freighter aircraft avialable (as it does today), Boeing was not interested in keeping that line open. Lufthansa had to to fight for their last 15 examples and there would have been more if Boeing had not shut it down. I always thought that the MD-11 would have been a much more lucrative line to keep open than the 717 since they MD-11 is the most sought after widebody freighter in the world. Its performance and economy as a freighter are unmatched and we will see the MD-11 around for many years in this role.
Major airlines with MD-11 fleets like SwissAir and JAL have commited most of their fleets to FedEx (although I am not sure what the current status of the Swiss-FedEx sale is) but others like Thai, KLM, Martinair, Delta,Varig, EvaAir, Saudi, Alitalia, World and Finnair plan to keep their small fleets in service as pax carriers a bit longer.