I am of the opinion that the current speed run conundrum is actually a simple fix. Add the Dark light body pieces to one of the other chests. Change the speed run chest's possible pool to Include all pieces of darklight, Finally fix the speed chest so its available active loot pool reflects that of the other triggered chests.

Ie if you blitzed cc and only got the speed chest and boss chest the boss chest would have it's slight chance of dropping its darklighty goodness. but when you hit the speed chest the noogety goodness is yours to fight over.

It is a win win for every one. Hard core players will not have to run dungeons until there brain is the consistency of runny tapioca. less skilled or geared players still have a shot all be it minor shot at the entirety of the available loot pool