Matt Miller
In Arkham, extra dice is always better. Every die in Arkham adds +1/3. But Arkham does a very nice job of limiting the dice you can add through the use of 'hands'. You only get two, and you you an only use two hands worth of spells/weapons* in a single attack. In Arkham, things which do add piles of dice (withering, etc) also require a roll to activate, and include an additional cost.
I recall some game that played with d10s. It made doing the mental math easy...but I think it was based on the ShadowRun style 'bathtubs of D6', where only a 1 counts as a success...which makes it worse than ShadowRun. ShadowRun, a 6d6 makes a success very likely. With a d10 system, you need 10d10. Making it a 1 or a 2 on a D10 doesn't alter it that much: 1/5 chance, vs a 1/6 on a d6--not worth the extra dice required.
**Recalls to me, before the 'Christmas Tree' twinking out, there was a rule that players could only have one magic item.
