At OrcCon 2012, the Living Forgotten Realms games—or the Battle Interactive at least, where time is of the essence—used average damage instead of rolled damage. That is to say, instead of doing NdS + M damage, monsters did N(S+1)/2 + M damage. Instead of dealing 2d8 +9 damage with his trident, for example, a kuo-toa lash would deal 18 damage. (That’s just an example out of Monster Manual 3, not necessarily a precise example from the games.) Critical hits, of course, still dealt critical damage.
How do you feel about using average damage? It sure speeds things up, but does taking away the monsters’ chance to really nerf a damage roll (as well as their chance to get a big devastating hit) detract from the fun (and from PC survivability)? Players, would you like or dislike it if the DM used average damage at your table?