Lanefan
Victoria Rules
This is exactly why I've had casters roll to aim AoE spells since almost forever. Roll really well and maybe you do get the sort of pinpoint accuracy referred to above, or at least give your friends bonuses on their saves. Roll average and you probably hit friend and foe alike. Roll really poorly and - particularly if you were trying to err on the side of caution - you might not hit anything of relevance at all, or (for fireball) the bead wrecks on some obstacle en route and the fireball goes off there.The issue is not the parameters of the spell: it is that wizards are assumed to be able to cast the spell with pinpoint accuracy in such a way that enemies get hit but friendlies in melee with them don’t.
Let me put it slightly differently. Go out to your backyard or other open space. Imagine that somewhere ahead of you your friend is swordfighting an orc. A little way to the left of the orc and your friend, but some ways further back, a second orc is fighting your second friend.
How confident are you that without moving or the benefit of reference points, you can identify a spot that the two orcs are exactly within 20’ of, but your friends in melee with them are not? Bear in mind that you have to do this within 6 seconds, and your friends lives are at stake.
And, because they're rolling to aim it means they can also fumble*, just like you can with anything else done under duress.
* - like the MU in an old game of mine, wearing a fireproof cloak and who fumbled with a fireball such that it went off inside said cloak. He pretty much melted on the spot while the cloak, naturally, protected all those around him...
