In discussing True20 stuff with Kad for the Shards of Jade group, we again got on the subject of alternatives to rolling the d20 (in a d20 system, of course), and the various merits and drawbacks involved in changing the system’s roll.
For starters, I updated the graph I made before, not in content but in style. I needed to play around with Gnuplot anyway, so I figured to give the graph a revisit.
The d20 roll obviously is a linear distribution of 1 through 20. With the d20 system, this randomness is modified in various ways to provide a result higher or lower than your roll, but nevertheless, the core of the process is the random number provided by the roll. On a d20, you have an equal 5% chance of getting any roll. In some ways this is interesting (such as often getting at least a couple natural 20s every session), but perhaps not desirable.
So, with some googling and thinking, a handful of alternatives were put together. (Okay, 3d10, drop the lowest is just there as a joke.) The impact on the game is nuanced, and not possible to quickly explain, but in short, all of the alternatives emphasize the character’s skill over random chance, by reducing the likelihood of reaching high rolls and causing opposed checks and ability checks to become far less about chance.
An in-depth look at a couple alternatives is here, ending with the same conclusion we’ve made: if you’re going to switch, switch to 2d10. We haven’t decided if we will switch yet, but I’m interested to see what others think. I think I brought it up, half-jokingly, at Iron Heroes once.