OK, so DW has part of its roots in the long heritage of D&D play. D&D next is in the midst of an odd playtesting cycle, and one of the interesting mechanics to develop is the idea of advantage and disadvantage adding a second die to the primary d20 roll and choosing either the highest or lowest result (respectfully of advantage or disadvantage).
I like this idea, and because I'm so enamoured of assembling dice pools, I've been mucking around with my group and playtesting a drift of the primary DW mechanic. Instead of adding bonuses or subtracting minuses to the base 2d6 roll, I've been adding dice to a pool and rolling that instead. If its a minus bonus then you take the lowest two results, If its a bonus you take the highest two results.
So a fighter with a STR of +3 gets plus three dice to her (base) pool of 2d6 for a total of 5d6 when rolling hack and slash and takes the highest two results. Similarly, the cleric with WIS of +2 but distanced from their god only adds 1 die to their pool for casting spells, taking the best two results out of three.
The hapless barbarian who has INT of -2 and is also stunned adds three dice to his pool for a total of 5d6 when rolling spout lore and keeps the lowest two scores for his result.
The results have been interesting...
Players LOVE assembling and rolling dice pools. They even go to the extent or clamouring for aid in order to grab an extra dice or two. Even extra minus dice are looked favourably on 'caus y'know, there is still the chance of rolling ALL sixes and getting a critical success!'
The results seem to be more swingy. I'm no mathematician, so I'm not sure of the probabilities, but a 10+ still seems as rare as before, and a 12 is still treated as a 'crit' by the gang.
Conversely, a miss on a 6 or less is a little more frequent, especially for characters with high bonuses (+2 / +3 / +4) who would normally only have a like an 8-10% chance of missing. This in turn lead to rather a hefty collection of XP (on a miss)
Rather than gear the XP cycle to a higher amount to curb the levelling, I turned XP into a spendable resource inspired by Burning Wheel's fate mechanic:
Fiction first as always... Explain how you have learned from your mistakes and how that would effect the roll and Spend any number of XP to add one bonus die per XP to your pool prior to rolling for a move. AND/OR Spend any number of additional XP to re-roll any result (one XP per die) after rolling.
I'm really liking this variant, and only having played one and a half sessions with it am still wary of its long term effects, but its been lovely to throw dice of different colours into the pool to simulate the narrative influence of additional 'effects' to the base roll. The players are having fun and are enjoying the 'push your luck' element to the XP spend.