I'm currently running a 2E game with modifications. (Some monsters are re-written, undead don't follow the standard pattern, dragons are not color-coded for the benefit of the PCs, etc.)

One thing I've done is introduce a very small number of Feats. Each player started with one, and I intend to give them one or two more, not automatically at certain levels, but at the completion of great achievements.

I just discovered that the d7, d14, d18, and d22 are available for $2 from Impact Miniatures, and that gave me an idea for a Feat.

The plan is to give a Fighter a d22. Then they could pick a single skill with which they roll a d22 instead of a d20. Perhaps I could do the same with a NWP and a d18.

How much impact would that have? I know the math - using a d22 would improve their chance to hit by X/220, where X is their probability of failure. So if they hit on a 2 or greater, the probably would go up from 19/20 to 21/22 - a change of less than half a %. But for a difficult shot, that you normally hit only on a 20, the probability of success goes up 8.6% - from 5% to 13.6%. So its impact is anywhere from almost nothing to close to a +2 to hit, depending on the circumstance.

This has the advantage, unlike many Feats, that its impact is greater for low-level characters, and drops to very little for high-level ones, who already have enough power.

So, how do you think it would affect the game? Would people think it was exciting enough to bother with? How would I need to adjust the encounters?

And what impact have I not considered?