In my understanding of game design, there are two styles of gameplay. Routine and advancement. Routine revolves around repetition of tasks and often found in strategy games, simulators, or games where losing is fun. It prioritize resource management, constant pressure and loosely defined intermediate goals. Advancement is a style for most RPG or FPS games, where you always meant to move forward, unlocking new places to be, new toys to play, new mechanics and playmates.
Those two tend to mesh poorly. Routine elements stall the advancement, forcing to delay new quests and new explorations. Mixing those two things makes neither here-nor there hybrid.
I'm distress at the fact that AAA games are trying to be everything at once.
Human knowledge is ever expanding, and the only thing we know for certain is that we will learn more. However the popular modern game design theory today lists 3 types of interactions in play (note this is types of play, not types of players (see Bartle's Taxotomy for the 4 player types (in mmo's)))
All Games have some mixture of these three gameplay types.
Improvise - Closely related to Emergent Gameplay
Games where you don't know what is going to happen next, so you have to act on the fly.
Rougelike games are a great example of this, as are procedurally generated games.
Rainbow 6 Seige is a shooter that strongly relies on this element since it's so easy to die, and the enemies AI & patrol patterns / spawn are randomised each level.
Impov rewards a player for using the tools they have to solve a problem quickly and decisivly as they come up.
Games that rely strongly on Improv tend to have more signifigant death penalties, because it keeps the tension high.
Practice -
The opposite of Improv gameplay. Relies on a static predictable setting. And Predictable AI.
Examples: Super Mario Bro's, all "Nintendo Hard" games, Dark Souls
The reward in practice gameplay is struggling against a very difficult challenge, and finally, eventually mastering it.
Speedrunning and Bullet Hell are the epitome of practice based gameplay.
Good Practice gameplay areas have a low penalty for death, because the areas are designed to kill you the first several times.
Plan -
gameplay where you have a rough idea of what you're going to be doing.
So you pre emptivly prepare for the channenges ahead of you.
THe primary satisfaction of this gameplay type is in reaching pseudo-Improv gameplay, and having the perfect tool for the job.
How does this relate to FO-4?
The death penalty in FO4 is losing all of your data since the last time you saved. This could be very significant, or it could be literally second. For the most part the gameplay is Improv. You walk through the wilderness, you see you pack of ghouls, you shoot the pack of ghouls.
This primarily breaks down when A) You walk across a lot of overland terrain, then B) You encounter a radscorpion or similar creature and die, undoing all of your recent work, or C) you walk into a too difficult Encampment or get 1-h koed by a Fat Man.
The game has a pretty basic set of rules for exploration. Hostile enemies are ok to kill (& drop loot when killed), your weapons can be used to kill them, the longer you take to kill them, the more hp you will lose, if you run out of hp you die.
Radscorpions violate the second rule, they can attack you while invulnerable and burrowed. Your weapons don't work on them in that scenario. They are also very very lethal. When you die to them, you don't think "I could have played that better", you think "Holy shit that was cheap, fuck radscorpions".
Fat Men are in the same boat, they don't let you react to them, it's entire if {enemy has fat man} then player alive == 0 (I accept they aren't 1-h ko on some difficulties, with some character builds).
Although entering a very dangerous building, and dying repeatidly as you learn every enemy location and perfect your path. That is a great example of Practice based gameplay in FO-4. The only problem is practice based gameplay thrives on close ended stats on the player's side. If the designer can't possibly know what equipment the player has going into the encounter, then they also can't plan enemy difficulty around it. It's why those types of dungeons are rare (they happen randomly not by design), and they are usually confined to the first 15 levels of the game or so, before you get good endgame weapons and armors. At which point the game becomes a bit trivial.
In fallout 4, brining a few grenades along just in case, is a poor example of plan gameplay. But it is an example nonetheless. A better example might be brining a ghoul-killer rifle, a Human-killer rifle, and a Mutant-Killer rifle. The big problem in fallout 4 is, most of the time one of your guns is just the best, and the rest are sub optimal. This tends to make planning which weapon to use, what chems to bring ectera, less rewarding. Because you rarely have that AH-HA moment. Where you think "man I'm glad I brought that rocket launcher, I would be in a lot of trouble right now if I didn't have it". I mean those moments do happen, esp with chems, but they aren't very common.