Why Re-Use Old Mechanics? Why Not Create a New System?
(Cross-posted from my Elf Lair Games blog, which you should also follow!)
This is a question I get asked far too often, and far too often it's with an accusatory tone, along the lines of, "what kind of a game designer are you if you can't create an original system?" or "Aren't you creative enough to come up with something unique and original?"
The truth is, I have worked with just about every kind of system you can imagine over my decades of game design. I've done stat + skill systems, roll and keep systems, fistful 'o dice and count kills systems, graduated die type systems, and more. All were fun, all were quirky, all were unique in some way.
I did go through a phase where I spent a lot of time coming up with new and different systems. I even designed a couple from the ground up that used cards instead of dice. One, the Hoyle System, used a standard deck of playing cards with each suit and the jokers representing something different in play, and another used tarot cards as a means of resolution, where the major arcana had specific game functions. While they were fun intellectual exercises, for the lion's share of my professional game work, I have almost always come back to tried and true.
Do What Works and Keep It Simple
Here's the reason. Tried and true works. If your game is entirely focused on your rules system, you're doing something wrong as a game designer (unless it's a board game; then the rules are what matters more than anything). But trying to come up with something "innovative" in an RPG is at best an exercise in futility, and at worst, arrogant pretension. The more "unique" your dice mechanic is, the more it draws attention away from the role playing and the more it forces attention on the mechanics, which is counter to the point of this kind of gaming.
There's an old truism in gaming that states you shouldn't roll dice unless you have to, unless the situation really calls for it. Don't roll dice to climb a ladder unless that ladder is rickety and covered with grease. Don't roll dice to find a piece of information that the adventure requires the players to have for the story to move forward. If this is the case, why would you create a rules system that takes longer to adjudicate and/or forces you to put more attention on the dice than should be due?
It might be fun to play with at your table but here's the simple fact: your system, no matter what it is or how it works, revolves around generating random numbers to mimic a probability. I've said this before, and I'll say it again: "innovative" dice systems are smoke and mirrors which in the end, use increasingly complicated means to just generate a random result, and overcomplicate things to no good end.
It's really simple: if you're going to generate a random result, just roll a die. The more complex you make it than that, the further away from the simple idea of role playing and shared storytelling you get. If your dice system is required to drive the story forward, your game has failed and it may as well be a board game. Dice don't (and shouldn't) drive creativity.
When you try to push something completely different out there, a full 99% of the time all you're doing is re-inventing the wheel. That's just putting a lot of time, thought, and effort into something that could be much better spent looking at other more creative aspects of your game. I've done a number of articles over the years about not re-inventing the wheel, about how it's better to re-skin something you've already got that works, than it is to invent unnecessary subsystems. As a game designer, I firmly believe you should always apply the K.I.S.S. principle.
Types of Systems
There's a few simple, straightforward ways to handle a dice system which again are tried and true, and to which I'll always come back. The first is the basic "roll a die and add modifiers against a target number" system. This can be seen in everything from the combat system in the earliest days of gaming to modern stat + skill vs. TN systems. Even basic roll under percentile systems fall under this category. It's easy, intuitive, straightforward, and quite simply, it just works and gets the Hell out of the way so you can concentrate on your story.
Next is the dice pool, count success levels system. In this version, you throw a handful of dice usually generated by a series of trait ratings, and count success levels. My own Cd8 system works off of this mechanic--throw a fistful of dice and every 7-8 you get counts as one "fist bump." Tasks are rated based on how many fist bumps they need to be successful.
Finally, and probably the least common, is the roll and keep system. In this system, you generate a dice pool, roll a number of dice, and keep a lesser number, often based on a skill. You might, for example, roll dice equal to your strength and climbing ability and skill, and keep a number of dice equal to your climbing skill, adding them together and applying the result to a target number. This system usually crosses over with one of the above: either you'll total the dice you keep against a TN or you'll count successes on the dice you keep.
The truth is, the vast majority of game systems on the market today fit into one of the above. It's just that too many try to mask themselves as something new when they're just a complicated coat of paint on the basic idea of generating a random result based on a simple probability.