Artificial Difficulty

[Reynhart]

In DMB/DF, the biggest thing stopping a player from completing a level lies in timing the jumps and interactions (the same would be true for IWBTG). The player being forced to test and fail does not make the challenge more difficult, it only increases the time requirement.

But in SMB or DF, you're not forced to "test" the wrong thing. If you have to reach a door, you'll have lava and chainsaws on your way, and you'll need to time your jumps to overcome these hazards. In a pure "trial and error", you'd have two doors in front of you, and you'll have to guess which one is the right door without any hint (And the wrong will kill you )
Of course, no games relies only on "trial and error" mechanics, or it would be blatantly obvious that no skill is required.

In progression, dying to meteors being too close for the first time in T9 or blackfire/whitefire in T12 does not break game flow.

This is something else altogether. Breaking the game flow is not a part of difficulty but longevity. In FFXI, if the whole party wiped in an arena, regardless of difficulty, everyone would have to go to their home point and crawl all the way back to the arena.

Trial and error is needed to gather information and more time is needed to solve the puzzle with this information.

The problem is when the only way to gather information is by failing. Blighted bouquet is really the biggest offender here...I really wonder how the first people found the trick...

An interesting point. Let's compare Titan NM, Titan HM and Titan EX.

Remember that you can't do a stronger Titan without having doner the weaker one. This means that Titan NM provides informations for HM, and HM for EX. So when EX come, the game can be quite brutal in its mechanic since you know how to deal with deal. Now you only have to do it with more stress and less ressources (comparatively)

When moving into raid content, the loop is at times so strong that the recovery window in terms of time or resources becomes so small that many players cannot catch it without outgearing the content. Whilst progressing such content with intended gear the strength of the loop is probably what makes players deem difficulty as "fair" or not.

Raids are the only content where you face one-hit kill mechanic without any prior experience. Even more, the game "tricks" you by using the same almost the same mechahnics with a slight change. For example, when you see the green crosshair mark on you, does the dive occur where you stand at the moment it appears or at the moment it dissapears ?

EDIT : There IS the game that only relies on trial and error !
DRAGON'S LAIR !