Taint in world was a reflection of taint in aura, it always seemed a little unwieldy to me.
The reverse, starting taint in a biome and possibly having it produce a taint flux, or to have it only spread via the purple webbing somehow feels more sane to me.
If, like railcraft, there's spawners at bedrock that make taint blocks, then you could never fully defuse it without picking up the spawner and dropping it on a torch, the biome would always eventually generate a new taint to spread, though as long as it can't spread out of the biome (most settings, it apparently can't) then the world is safe (as long as you don't let the biome spread in the settings either).
On the other hand, maybe the starting taint block is an entity restricted to spawning in the biome.
Or maybe there's a 3rd way to do it, or 15 other ways to do it.
For each way to do it there's ways to handle it, up to and including the cfg file.
As has been said elsewhere in the thread, most of taint science was about making taint less dangerous. It felt a bit incomplete. Yes you needed to tame taint to get to the final tier of anything. Yes you needed to tame taint just to live in the world, but it didn't seem special, just a required chore.
So, taint as a researched aspect?
Taint to unlock a new tier of items? A vampiric touch enchantment?
Due to advances in vanilla life is very different. I can picture a device that, instead of having you select the enchantments for the item, it selects the enchantments and writes them into a book. You could lock enchantments so they can't show up randomly, but can be written to the black tome, and then put to the items with an anvil.
