Maxperson
Morkus from Orkus
No matter how much you try, there is no one true way of 5e gameplay. It's an absolute fact that you are wrong, since I've played 5e several different ways.@Maxperson You are demonstrating the other big reason why 5e enforces OneTrueWay of gameplay.
You place too much weight on predictability. So what if I can predictably say that we will trigger pretty much every trap we come across because we are relying on darkvision. That doesn't make triggering all those traps a good thing. So what if I can guarantee us to be ambushed and surprised a ton because we can't see the enemies coming. That doesn't make it a good thing.It's pretty significant because Darkvision is reliable predictable & always perfectly av in ways that no light source can be
Here's a story about darkness
Darkvision is the ability to always know that you have a perception check of N against the unknown & to do it with no risk of exposure.If you know the creatures cannot hurt you, they will not hurt you. Because they are not real
If you think the creatures can hurt you, they will hurt you. Because they are real to you
You fail to understand the usefulness of darkness to a dungeon crawl. Disadvantage on a perception check is [2d20 drop highest+mods=N not an unknown. The player knows exactly how much risk a patch of darkness poses can never be left scrambling for a snuffed/fallen torch & will never find themselves trying to wave a visible torch around at unseen creatures in the distant darkness. Not knowing the colors of the unknown things in the dark is a thing of zero consequence
Light is also just as predictable as darkness. Groups I've DM'd for and played in have been using continual light coins since 1e. Now the darkness spell can overcome that, but it also overcomes darkvision. Torches were almost never a limiter in any way. You bought them by the dozens and they were obsolete to the continual light in a few levels.
Those same rules have been present since the 1970s.There you go showing more rules & widespread abilities to trivialize the usefulness of meaningful darkness to a dungeon crawl. Bullseye lanterns trade the downside of being heavy & single directional for the ability to hide the light without needing to snuff then relight the lamp, 5e is so generous with carrying capacity & things like darkvision/light cantrips/etc that the weightof light sources is pretty meaningless & the benefits are not even worth considering.
There are no inherent problems in the 5e rule set to sandbox games. None. Safety and durability are irrelevant to being in a sandbox. As long as the DM can create a world for the players to explore and the players can pick and choose where they go, it's a perfect Sandbox. What rules prevent me from doing that in 5e? Not one.l assume that you recognize the other noted problems posed to sandbox games in the 5e ruleset too given that you didn't even mention the ways that extreme durability & safe trivialized recovery anywhere
Whether you think PCs are too durable and safe is a completely separate metric that has nothing to do with most playstyles.