Lots of people like the World of Darkness games. The settings are fun and set up lots of hooks. The hardest part of rewriting these games are that the supernatural powers that PCs have access to are all idiosyncratic -- they all have their own rules, and usually each level of each power has different rules. Mage: the Ascension has 5 levels of 9 spheres with an average of 3 mechanically distinct rotes per sphere-level. 9*5*3=135. That's too much for a rewrite.
Now, most of the powers' rules are passing-fair. A minority need to be re-written or banned to make a playable game, and actually at that level of granularity, every GM is going to have different lists of what to ban and what to modify. A lot of that can even be handled on a case by case basis by allowing a core menu of powers, and then allowing players to "apply" for a power not in the core set.
But the base system had to go.
The base system of rock-paper-scissors and comparing traits was retained, but traits were never spent. My version had six stats, ranging from 1-10. These stats never changed during play.
Characters started with a sum of 10 in their Physical and Mental (say, 5 and 5), plus 5 Willpower and 1 Arete. Notice Social is gone. I could have included it, honestly. And I would recommend for games like Vampire, you do. I personally think non-magical social conflicts should be handled by roleplay, but I can see why you might disagree.
There were 5 consumables that players were required to track on their character sheet with a pencil:
- Temporary Willpower
- Backgrounds (most backgrounds were permanent; but things like Influences and Resources had temporary expenditures).
These are still too many, of course; but it's a lot more manageable without tracking traits. Characters started with 5 skills 7 backgrounds, etc. - Just like the core Laws of Ascension system. I created a comprehensive list of skills. "Comprehensive" means there are no skills not on the list that will be allowed in game and no use for a skill that is not mentioned in the list. To know what your skills can do, you just read the attendant list entries.
My text was largely the same as the Laws of Ascension book text, though I eliminated all social skills that were used to initiate social challenges -- there weren't many of them. Intimidation stayed in - it tested Physical or Willpower against Willpower.
Characters could also take Merits and Flaws from an approved list. Some of these were modified.
The main benefit of rewriting a game so that it is still compatible with the old material is that you can just refer back to the modules that your rewrite didn't affect at all.
Backgrounds were unchanged. So I just plugged in Laws of Ascension here.
Sphere magic's casting rules were totally rewritten to make them more LARP friendly. This was a short section that granted extra successes for LARP-worthy behaviors, rather than rock-paper-scissors tests. E.g. you could get extra successes if you acted out casting for 5 minutes or brought props, and so forth. But the spheres themselves and what each level could do, and even the majority of rotes from Laws of Ascension were kept. So I didn't have to rewrite the spheres.
And that's about it!
In essence what I did was write a whole new base system -- far simpler than the original -- compatible with a limited selection of the existing character abilities. The new system simplified the game and shortened character sheets to the point where characters carried around an index card with their stats and skills on it, one for each piece of equipment with stats (e.g. talismans, weapons and armor) and one for each of their rotes.
Imagine doing the same for Vampire: One index card with stats, one for each piece of gear, and one for each level of each discipline. If you kept characters fairly low-powered, that's no more than 10 cards. You could either have players track Blood, Willpower, Abilities and Backgrounds spent on the stats card or you could have them use chits for some or all of these (Willpower and Blood, for instance). In fact, the appeal is so strong that even though I have no intention to actually run a Vampire LARP, I might write this up and post it on this blog for everyone who wants to take... Comment if you would like that!