This talk about builds and all your tips is exactly what I have a problem with.
Perhaps it's that we have different expectations or interpretations of what the different levels of difficulty mean to use.
My view/expectations are:
Explorer is "story mode":
I should be able to complete it easily, powering through everything. Any character build should be able to complete the game.
Classic mode
I'd call this "normal" difficulty.
In this mode I'm expected to expend effort. It should be challenging to a new player, I need to ensure I have a fairly well balanced party, that I make good use of the mechanics etc.
I should be able to complete the main plot-line with all the resources available to me; I shouldn't have to do all the side-quests, etc to make sure I have enough gold/level.
It should still forgive the odd mistake in character builds/choices, combat decisions etc. Consumables should not be necessary to win all but boss fights, and can act as a safety net for combat or build mistakes.
I'd expect this level to be for anyone experienced with D&D, and/or CRPGs.
Hard
I need to be careful with my builds. I need to have played the game through at least once, have a good knowledge of all the mechanics and need to make careful decisions in combat.
To succeed I need to be correctly combining abilities/spells, stacking bonuses and making good use of consumables.
Very Hard / Insane
I'd expect to need to know the game extremely well and have a very good knowledge of the classes and abilities/skills and have to build them into a strong cohesive unit.
Combat mistakes will generally get me killed, a bad build or class combination will prevent me completing the game.
Consumables are essential in combat, crafting is essential and I should feel constantly short of resources.
I see this level for the perfectionists, the min/max'ers etc.
Conclusion
I see the current difficulty level as somewhere between what I call Hard/Insane.
Now perhaps my interpretation/expectation is wrong. Maybe you feel classic should be what I consider hard mode. At that point we're just talking about semantics.
I see "Classic" as "normal" difficulty. From your posts, I suspect you see it more as a "hard" difficulty.
If your interpretation is correct then there's a difficulty level missing, in my view, between explorer and classic. In my interpretation you'd want to be playing not "classic" difficulty but something higher.
Let's see if Larian gives us some more difficulty levels.
