The biggest Charm conversion difference is in defensive Charms. This primarily means that the dice caps for attack and defense tend to become different.
Now, the Standard Solar Assumption is that a maxed Solar attack is within one or two dice of a maxed Solar defense. That is, a Solar with FFBS and FLB up has a defense of 20 dice, which is comparable to a maxed Solar attack. However, this doesn't quite work as expected in the nWoD; the passive Defense trait plays merry hell with it. Additionally, the base assumption in the nWoD seems to be attackers will usually have a two to three die advantage over Defense most of the time.
Now, my base impulse was to let Solars add their full Skill to their Defense with Charms. This lets them add up to 10 to their Defense, and gives them a Defense in the 12 to 14 range easily. Their attack, however, is Strength + Weaponry + Damage; not even counting stunt bonuses, letting them add Strength + Wepaonry with a dice adder would easily grant an attack pool of 23, meaning a 9 die advantage. Which means 3 successes on average.
On the other hand, letting Solars add Dexterity + (Skill) on top of their Defense results in even maxed Solar attacks going down to a Chance Die. And that's no good.
Giving different caps to different forms of Defense addition is a thought, but not really ideal either, since it makes unparryable and undodgeable attacks have different values.
The more I think about it, the more inclined I am to completely rip and gut the old Charms; steal the names but re-write them from scratch.
Athletics subsumes Dodge, for Charm purposes.
- Solars and Abyssals can add up to their Skill to their Defense.
- Dragonblooded can add dice up to their number of applicible Specialities, to a maximum of 3, to their Defense.
- Lunars can add up to their Defense (the lower of their Dexterity or Wits). They can also buy Armor up to half their Stamina.
- Sidereals can add up to their Essence to their Defense.
These simply replace the old requirements.
Now, on the other hand, since Defense has a base value now, it'd be effectively 1/4 the price of attack if the 2 dice per mote was kept. So the cost of Defensive Charms needs to be on par with offensive Charms.
... Meh. That math doesn't work out. Mur...