After Otis, I came up with:

Some Taint goals:

* One, single, simple unified mechanic.  I'd prefer it to add no
  dice-rolls to the game.

* Taint is almost always safe to acquire.  It should be about on the
  level of a minor wound: not something you seek out, but something
  that doesn't eit your character forever just for a bad roll.

* Matrices move you from "minorly eitful, but you can suck it up" to
  "Just fine, thanks."  There should be no risk of bad effects when
  using a properly functioning matrix.  A matrix with a spirit-sword
  stuck through it probably isn't functioning.

* Small stuff should not actually be preferable to big stuff.  You
  should be slightly reluctant to go raw, but once you do, you might
  as well go big.

* There should be a cap on thread-weaving: there should be a certain
  number of "safe" turns thread weaving, some in the danger zone, and
  then some where you'll be horribly lucky to not collapse your matrix
  or something. Thread weaving's cap has nothing to do with Taint:
  it's really there to make sure that High Rituals are cooler than
  improvised sphere spells, and that the flexibility of the
  sphere-magic mechanic doesn't run away into Unlimited Powah.

Some rules to implement the above:

* A good way to get unification is to say Peripheral Essence causes
  Taint, and all spellcasting counts as Peripheral Essence.

* Matrices absorb the Taint for you, harmlessly dissipating it into the astral.

* Whenever you spend peripheral essence, add 1 to your Limit.  When
  your Limit hits 10, you limit break (if an Adept) and it resets
  (whether or not you're an Adept).  If you're Horror Marked at the
  time, worse things may happen; again, Horror Marks are quite rare
  and show up as plot devices, not as generic weapons.

* The number of threads weavable to a single spell is a function of
  the sphere.  I think 2+(sphere level) (so 3,4,5) works.  Got to run
  the numbers on what that makes possible/impossible.

-Brian


How do matrices unskew?  Options:

* When you sleep, they unskew?

* Spend something -- willpower seems too expensive, essence too cheap?

* Reattuning clears all skew?

Reweave needs to be tied into the above.