Mourn said:
And I think you're too fixated on fireball, since that's the spell that constantly comes up during this argument, despite us having no idea what the 4e version actually does.
We know there are spells that affect lots of opponents at once and they require attack individualized attack rolls.
You're dodging, I think, because I've got a very good point.
Some spells will require "attack rolls" but obviously aren't guided by the precise angle of the wizard pointing a finger. Some will obviously perform this behavior (hitting lots of foes) and go even further such as hitting lots of foes some of whom aren't visible to the wizard at all (i.e. dropping a fireball at the corner of a hallway; or on a group of foes some of which are invisible).
I think it's reasonable to assume these AOE's will affect invisible creatures, creatures down the hall, etc.
I think one of these AoE's will be called fireball, but maybe they'll decide to call it blast-of-fire.
Either way it's a problem with your logic. Insisting that the emperor's wizard doesn't know fireball because we haven't seen his spell book yet isn't much of a logical defense.
Your explanations and interpretations are all reasonable. They're one very specific extrapolation targeted at insisting that MI -has- to work differently.
You can attempt to avoid alternative possibilities that allow this, but it's doesn't make your argument any stronger (or weaker). It remains one (strict, game limiting) possibility.
You're dogged insistence that this is the only possible way that it could work has defeated me. I shall post no more on the subject.