I like the ‘tiredness bar’ idea since it seems more grounded than a somewhat artificial gear durability loss.
I also like the corpse run idea because while providing you the tools to safely return to where you died (Thomas said you wouldn’t lose your equipped gear nor consumables), it also feels more punishing and grounded than gear durability loss. Given that there are some indescructible gear sets in the game, with some effort and planning ahead - you can avoid the consequences of constant failures altogether.
If you remember to activate the whispers you’re passing, retrieving the lost gear sack shouldn’t be much of a hassle: you don’t need to go far and you have the tools to get there.
I’m all for corpse run - maybe as a realm or difficulty level parameter to cater to all tastes ?.
But I’d also prefer the ‘tiredness bar’ over the current gear degradation system, since after a few failed attempts at beating Darrak, you still need to return to Sacrament to rest and rethink your strategy / upgrade your gear. It’s essentially the same ‘degradation system’ with shrinking damage output, but the thing being degraded is you, not your gear, which feels more believable and grounded than all of your inventory losing a flat chunk of its durability at once.