Do you think that the difficulty is important in defining the level of quality in a game’s combat? For example, if the Souls games were a lot easier, would the combat’s simplicity become more of a problem? Is the average Zelda game’s combat the equivalent to a much easier Souls game?
The average 3d Zelda game isn’t really equivalent to the Souls games because even if you run a 3 hearts challenge in Zelda, the game won’t get any deeper. I did this in Breath of the Wild, and the additional penalties aren’t bringing out more efficient use of alternative options, the base combat system largely lacks alternative options.
Souls did something super smart by having attacks from the player come out slower, it put the player on the same pace as enemies. It then has other factors like stamina, which help connect the system together, requiring you to manage that factor over time in addition to the complexities of combat. Stamina also discourages shield use, makes the shield system actually work by giving people a reason to not block. Dodges have iframes instead of purely being evasive. Etc.
You can’t just make Zelda games harder and end up with something like dark souls, you need to make the enemy designs more complex, and the design of each move more multi-faceted.
Difficulty is important for making players pursue the higher efficiency of using all their options, but it’s not everything. Difficult games aren’t better by default, and making a game too difficult can end up making the game extremely restrictive, eliminating depth from the game.
You want to encourage actual use of the widest array of options. Which means first, those options need to actually exist, and second that the difficulty needs to be high enough that they’re necessary, and not so high that they’re rote.