Lightblade is definitely the hardest traditional Strike in the Nightfall rotation, and it's up there in the overall rankings. Compare that to ones like SABER and Warden of Nothing, which are sub-15 minute cakewalks for the typical team. Your Resilience tier is only one part of the survivability equation. One of the most common things I see is people using reserve mods on chest armour. They're good for swapping to before rallying, but the slots should almost permanently be occupied by resistance mods. Each one is a stacking 15% reduction to that damage type and are more than worth the cost. Then you often need to add subclass verbs in; if you're not making use of the likes of Void Overshield, Woven Mail and Restoration then you really should be. Alternatively, have some form of CC - Blind, Suppress, Freeze, Suspend. Every subclass has tools for survivability at its disposal. I don't think that the difficulty levels are perfect, but the old system had just as many flaws. Legend and below was meaningless and you could waltz through it without caring what gear you use or what Champions and shields the activity had. The jump to Master was huge, and it was less accessible than GM because of the higher level recommendation. The current system makes the gaps a lot smaller, and enforced level caps mean there's no need to grind to be at-level for such content.