Johnny Q wrote:
I suspect the reasoning is that attacks that affect multiple targets are weaker than single target spells with a similar mana cost. The reason for this should be obvious. So, additional strength is more valuable for those attacks that can hit multiple units.
Ranged +1 and Melee +1 buffs are very inexpensive. (3 mana for ranged +1, or 5 mana for melee +2) Therefore they have to be limited in power.
Ranged +1 can only affect one attack per action. For example, if you cast a fireball you get +1 damage dice. If you cast a chain lightning, you get +1 damage dice to the first attack, but it does NOT add dice to the subsequent attacks. (so you'd get 6-4-3-2-1 dice instead of 5-4-3-2-1)
Because a Zone attack can hit a ton of stuff at once, it would simply be "unfair" for Ranged +1 to provide multiple additional dice at once. Therefore zone attacks are completely unaffected by buffs.