It doesn't matter if they're intended, being intended doesn't make something balanced. But we don't really know how they intended the crafting skills to be used, having 100% cost reduction could've been an oversight. It really doesn't make sense that they'd intend for people to reduce mana costs to 0 though, considering it makes other stats and perks completely obsolete.
No one is insisting only the maximum potency applies either. I certainly am not arguing that every potency below that is fine. I don't quite understand what point you're trying to make with that part of your post. Sure, there's a low potency available if you don't perk alchemy or enchanting, but that clearly does not make them balanced just as melee is not underpowered because you don't deal enough damage with an iron dagger.
I mean that you have a choice on what suits your playstyle best.
These advocates of a 'nerf' want to control how everyone
else plays their game, and that grinds my gears.
Its perfectly possible with the crafting skills, difficulty slider and choice to level combat/ noncombat skills to tweak Skyrim just to your liking.
I know I did, with my Ghostblade that does 88 damage and no perks in one-handed.
I like the measure of control Skyrim gives you, and if one end of the spectrum is godlike characters, so be it.
I dont want anything 'nerfed'.
hardcoe mode, good idea. Tweaking enemy AI, why not. Dawnguard added some new high level enemies, awesome.
Addition, not restriction.