|Dice, dice, dice, dice, dice.|
I command you to read this article on dice probability. Very thorough, very interesting, and more importantly, very easy to read. For a guy like me, it's much easier than listening to a friend of mine ramble on about probability.
Go ahead and read the article then feel free to come back.
Good? Then let's protrude into how these applications of dice to the same type of roll affect the Optional System.
More Dice Is Good
While the article's feature is D&D, it's the application of 2d10 over 1d20 that catches my fancy. The Optional System relies on multiple dice; if you want a better shot at success, you need more dice than your opponent. According to Glimm's breakdown, multiple dice provide for a greater than average chance of being... well, average. If you simply roll a single die to achieve a goal, the odds are not in your favour to accomplish some of the most basic, expected tasks you can think of and that seems a bit disconcerting, doesn't it?
Let's say you roll 5 dice in total, each from its own dice group. For the most part, they will roll their average not in unison but as an overall average. While one die may max, another will be tragically low and the two will balance out to a nice medium. In this way, your character's odds of performing the standard effort for a given task is greater than your single die games. Therefore, your OS heroes are performing exactly as they have been trained to do.
The challenge comes in rolling higher than your opponent or the difficulty dice and that's where more dice comes into play. The average of 6 dice is higher than 5 dice (for simplicity's sake). Common sense says that if your opponent rolls 4 dice against you, you pull out a fifth. That's the Chicago way.
So why use so many dice? Many other indie games (such as "Kiss My Axe" by Swords Edge Publishing, which I played last night and need to add to my Links list) use a pair of dice to achieve the same results. There are two answers for that, or rather two subsets of the same answer.
Reason #1: You Have A Problem With Dice, Son?
Anyone who's played a spellcaster in any Gygax-inspired RPG has grabbed all their d4s or d6s, borrowed some off their friends, and dropped a massive pile on the table. The clacking of a fistful of dice smashes the table and rolls frantically across the map, knocking over a mini or two, falling onto the floor, never to be contained by your physical restrictions. As soon as we all started rolling dice, we started thinking of ways to roll MORE dice in one shot. Don't deny it. Everyone who enjoys a sip of wine with dinner has been drunk. This system embraces that thrill for everyone, not just casters or daily powers.
Reason #2: There's Always A Possibility
"I can't beat a 27, all I have is a d20." In the short amount of playtesting so far, this phrase has come up a couple of times and it's the result of years embedded in target numbers. Concrete numbers to set your dice to, instantly calculating your odds of success, and working with limited additions to increase your odds. If your best magic weapon isn't enough to improve your chances, the best you can hope for is a +2 bonus for cover or flanking your opponent. Not any more.
Hiding behind a tree grants you +1d10 circumstance dice; spend a skill use for another +2d6 trained dice; activate that power for +1d8 power dice; and if all else fails, take a shot with +1d4 bonus dice and tempt fate. Even then, your dice could explode. There is no such thing as an impossible goal; you are only limited by the devices you create for your character, be they training or spontaneous advantages.
When in doubt, roll more dice. No more will I teach you today. Tired, I am. Rest, I must.