You can have the same effect of Coral with Merigold's Hailstorm, which is a neutral Silver spell. So if we're to discuss any nerfs to Coral, we're also implying nerfs to Hailstorm. They are strong cards, but I honeslty don't feel they are that OP, also I like their effect in the game. Even so, because of its flexibility I believe they should add a limitation to that effect. Maybe something like:
- Damage the three most strong Units on a row by half their Power (rounding up and ignoring Armor);
- Damage the strongest Unit on a row by half its Power (rounding up and ignoring Armor) thrice in a row;