After you cast a spell, you are briefly at a penalty to cast further spells. Small Magics = -1d6, High Sorceries = -2d6. It only takes about a round of rest to recover a d6 of penalties, so you can cast Small Magics at the rate of 1 per round at a cumulative -1d6, then forbear from magic for that many rounds to get back up to full value. Lets you get off one big spell in combat, but afterwards you'd best do something else for a bit.
RPG.net thread had an interesting idea... folks who rolled a mix of successes and failures on their dice could get Chi points back by accepting a consequence in proportion to the number of failures rolled. Stuff like "You succeeded at X but that caused Y!"
Personally, I kind of prefer something like that old Star Wars homebrew had...
When you fall short on a test, you can offer a Complication to the GM in return for 1 to 3 additional successes.
Think of something that could go wrong for your character and suggest it. If the GM likes it, it becomes fact in the game and you receive as many additional successes as the Complication was worth.
The GM can also refuse with "No, that doesn't sound appropriate," "Sorry, that's already going to happen," or "That's not worth X successes."
1 Success: annoying hindrances like breaking your tools, embarrassing yourself, displeasing an important NPC, etc. These can generally be undone with a little effort or a few rolls.
2 Successes: serious threats like hurting yourself severely, triggering an attack by a dangerous foe, alienating an ally for a long period of time, breaking a difficult to replace item.
3 Successes: really painful concessions like being immediately incapacitated, being maimed (losing an eye or paw), having an ally perish or turn against you, losing a unique item of great personal or material value.
Physical:
Shaping (are there enough to merit a separate category?):
Mental:
Divination:
Spiritual:
So, how about this... a rating of 1d6 in a skill is "trained" and says that you have some training in the basics. You can perform Lore checks, where you analyze or identify things using knowledge specific to your field.
For example, Swords +1d6 would allow you to roll Cleverness + Swords to appraise someone else's Swords skill or to analyze the quality of a blade you found. People without any appropriate skills cannot succeed in lore checks like this, regardless of how high their Cleverness is. So someone with only Cleverness might be able to appraise a foe's total combat ability by watching him fight, but couldn't tell you how much was Athletics and how much was skill.
A rating of 2d6 is "well trained" and says that you are well-experienced in the area. You can now drop 1d6 from your rolls to perform Minor Stunts. Things that are related to your ability but not particularly unbalancing.
For example, Swords +2d6 could take a -1d6 penalty and throw a sword like a spear, attempt to disarm a foe or entertain a crowd using swordplay instead of Perform.
A rating of 3d6 is "master" and says that you have pretty well mastered that art. You can now drop 2d6 from your rolls to perform Major Stunts... fairly unbalancing maneuvers that are still related to your skill.
So, Swords +3d6 could take a -2d6 penalty and write his name in a foe's clothing in the middle of a duel, make an especially deadly strike (-2d6 to hit, but +4d6 damage dice if you do succeed) or attack multiple foes simultaneously (all must resist the number of successes you roll).
Magic now works largely the same way except that the difficulties are called:
Wild Magics (no skill): you can perform Small Magics, but unless you get at least 2 successes, the spell does something similar to what you wanted, but less specific and possibly in the wrong direction.
Small Magics (no penalty): small spells that can't win direct contests but can work indirectly in appropriate situations.
High Sorceries (-1d6 penalty): like Small Magics, but stronger, to the point that they can oppose people directly and still win. Also adds some new and better Small Magics. High Sorceries incur 1 point of Magical Harm unless you sacrifice at least one success.
Forgotten Mysteries (-2d6 penalty): adds some really impressive effects that always incur 2 points of Magical Harm unless you sacrifice extra successes to counteract them.
Or perhaps... -1d6 is Large Magics (minutes) and High Sorceries (rounds).
-2d6 is Large Magics (cast in rounds) and High Sorceries (cast instantly).
Telekinesis, Mind-affecting, Divination, Spirit-affecting, Fire-casting, Shaping. Should Divination and Spirit be lumped together? Am I forgetting any?
My list o' 7 was Shaping (includes Healing), Telekinesis, Spark, Scrying, Mesmerism, Illusions and Calling (summoning/telepathy).
I'm seriously considering merging it into Physical (shaping, tk, spark), Mental (mesmerism, illusion) and Spiritual (scry, calling) magic.
Magic should probably also be slower... say a base casting time of two full rounds for small magics, 2 minutes for high sorceries and 2 hours for forgotten mysteries.
A thread on RPG.net had a cute way of handling general-purpose magic in Spirit of the Century.
You took a spell-crafting Stunt that let you use your Mysteries skill to declare Aspects that fit with your magic, like "Can climb sheer walls like a spider" or "Levitating" or "Illuminated with ghostly light". Tagging this once was, naturally, free. Making use of the Aspect more than once required you to spend a Fate point.