Turanil said:
Now about magical items: Proliferation of magical items will have to be stopped by another system than absurd costs. My idea is: magic by its very nature is not something that can be rationally mass produced, it's not something akin to industrial manufacturing.
No need to change the system in order to do that. It works that way right now. Unlike mechanical items which can be mass produced in assembly line fashion, magic items require unusually skilled labor to create (you have to be able to cast level x spells for most item creation feats and you need the feat) and furthermore consume some kind of a mystic portion of the creator's life force (xp). They're not the kind of thing you could do with an assembly line unless you have hundreds of level 3+ wizards and clerics in the same place in your world. (And if you have that, you're into the mass magic anyway).
Of course, if you don't really mean "mass-produce" but rather "produce in relatively large quantities" that's not true. A wizard's DM should expect the wizard to write quite a few scrolls over the course of his career. A character with Craft Wondrous Item will probably produce at least a dozen wondrous items as well. However, none of that is going to be on the scale of true mass production even if it seems like that compared to games where 12th level characters are killing each other over a single, precious potion of cure light wounds.
So, if PCs want to manufacture a few potions of cure light wounds, but as a DM I don't want them to make dozens, I will require strange mystical ingredients. I will have to think about it, but it can be Troll blood kept in a special fragile container, and the troll must be slain during a night of full moon, and half the blood spilled over the Earth to appease the spirits of whatever, all of this done by the one who will do the potions (or it doesn't work), and so on. You see the idea: the conditions are such that you CANNOT obtain ingredients in large quantities just because you have all the money necessary.
So then, here's the question: can a character who spends a feat to be able to create magic items get enough use out of it that he doesn't say "man, what a waste; I should have just taken Spell Focus." The follow-up question is this: "do you want the butcher's knife, scapels, and glass vials to come out after the PCs kill every monster?" (We just killed a basilisk! Quick, let's take some of its blood--that's useful for potions of remove paralysis--its eyes (eyes of petrification, of course), its skin (for a cloak of resistance), and its claws/teeth (an amulet of natural armor).
So, there are two possibilities:
1. Either your restrictions are so heavy that item creation feats become useless and PCs will never create items (as in your example above). This, of course, raises the question of why any NPCs ever bother with it--or even how they are capable of it (3rd level clerics aren't going to be killing a lot of trolls on the night of a full moon or any other time and since low-level clerics are the primary source for potions of cure light wounds, with those restrictions, they should be non-existent).
2. The PCs are willing to live with the restrictions. "OK, I'll need a teleport spell to get to the trollfens and a find the path to get to the nearest troll, then we butcher it, collect the blood and teleport back to make the potion."
I don't really see either one of these adding to the game--especially if you're going to make 10th and 11th level PC role-play out killing a troll in order to make a single potion of cure light wounds.
Plus magic must be done as works of art (Van Gogh paintings couldn't be mass produced!). Etc.
You have some rather strange ideas about art--probably coming from popular conceptions about "great" art. I wouldn't think that all magic (even potions?!?) were supposed to be masterpieces on the order of Starry Night or the Mona Lisa. If potions and scrolls are more along the lines of 18th century locket portraits, comic books, or television episodes then it's a lot more conceivable that you could make a reasonable quantity of them while still doing them "as works of art."
Sure, adopt the art model for magic items, but your Mona Lisas, Davids, and Starry Nights are going to be the +3 Holy, adamantine, Evil Outsider Bane greatswords of wounding and robes of the archmagi not potions of cure light wounds and +1 swords. Potions of cure light wounds are more akin to the character portraits that local artists draw at conventions and +1 swords might be Harlequin romance novels. They're certainly made as works of art, but no-one will mistake them for great works of art.
So, I remove the absurd costs, but whatever the reason, it's impossible to create more than one or two magical items every now and then, even if it only costs 10 gp and can be done in 10 minutes!!! (It's fantasy and magic after all)
I can't think of a better way to say "Don't bother with item creation feats in my game; they'll only be useful on the third Tuesday of the second month of a leap year." Low costs and low time consumption don't make up for being restricted to "one or two magic items" "every now and then."
Then again, this raises another question: if it's so darn hard to make magic items (a caster has to track down and kill a troll in a special ritual on the night of the full moon and then suffers a chance that the fragile container breaks on the way back, making all that effort turn out for naught), why on earth is he only going to charge 10gp for it? That sounds like a recipe for making magic items
more expensive rather than less expensive.