The fireball hand grenade

You might have heard me complain about fireballs a couple of times, so I hope you'll forgive me for trying a new fix to a problem some of you might share. The fix is really simple and does not significantly nerf MUs (in fact, I'm not sure it is enough).

Usually, when an MU throws a fireball at a group of goblins, things like saves and damage rarely matter - goblins within blast radius are toast. Which is fine, but it gets weirder and weirder to me when the MU can instantly kill a group of orcs, lizard men or even bugbears.

What if we just roll damage as usual (say, 7d6 for a 7th-level MU), but that is the TOTAL damage dealt. So, against a group of goblins, a weak damage roll (say, 20 points) and a successful save would reduce the number of goblin casualties to only two or three.

The damage is distributed as the GM sees appropriate - think of the fireball like a hand grenade! Most of the damage hits the center, shrapnel spreads outward.

This logic seems to work for groups. Against a single creature, the fireball remains equally effective. If you want to change that, you can just decide that, like a grenade, the main target gets most of the damage but a part of it (say, half of the damage, round down) is spread around.

Lightning bolt could function similarly, but maybe I'd let the MU concentrate all damage into a single creature or create a "line" of damage that diminishes as each creature is hit in a straight line. This spells has not been as common in my games, however. I'm even tempted to treat dragon breath in similar way (well, as a flamethrower) and let fighters jump with their shields in front of wizards when needed.

Anyway, I like this idea because it makes a 10d6 fireball very different from a 5d6 fireball against a group of lesser foes, which gives the wizard a real sense of progression without making him overpowered in comparison to fighters. Thinking of them as grenades makes them feel more grounded and tactically interesting, giving MUs interesting choices of where to aim - and it is also reminiscent of the original Chainmail origins that treated wizards like artillery.