That was in part due to Bungie's poor balance and the introduction of power disabled/minus power. Bungie throwing in -5 power to base dungeons/raids just made the experience worse and Ghost of the Deep is the biggest form of evidence there. Before you could go 20 power over, but then a small amount of the community liked the disadvantage crap from Pantheon so Bungie threw that into everything. Doesn't help Bungie made those 2 bosses some of the tankiest pieces of garbage in the game. They even made them tankier by making Arbalest not one-shot their super shields before DPS. Takes away the fun and wonders why their player base dropped before Salvation's Edge came out and is still dropping now.