I disagree with this take. The dungeon is supposed is a raid in terms of complexity but with mechanics that are designed to be done by 1 person to protect that solo flawless mantra. We are seeing the evolution of difficulty rise due to power, movement, and skill creep. Raids themselves started at simply stand on plate and shoot oracles and grew to what you see in Salvation's Edge. They will continue to evolve to match what guardians are capable of and as we get better and better stuff the difficulty ceiling will rise proportionally as well.