[Kristoffer O]

AoE hits everyone in a square. Thus Falling Frost is not affected by shields. Same with Gifts from Heaven etc.

Flame Bolt targets one unit and can be avoided or parried. Shields are useful.

Lightning tends to strike conductors. Anyone in a square can work as such. Thus Lightning Bolt has the flag 'hit' to implicate that it will automatically hit a target in the square it strikes. Shields offers no protection.

Blade Wind sends out a multitude of mundane missiles. They can all be parried with shields.

Earthquake targets an area, but will not strike those who sucessfully passes a def roll. This is a pure def roll, so shields will only be bad here, since they lowers defense before adding pary. Not much use to parry the ground.