[ANNOUNCEMENT] Heroes 3: World Tournament - an add-on for tournament games.

The Eagle Eye skill allowed you to immediately copy all of your opponent's spells into your spellbook upon contact. In other words, if an opponent attacks you, their spells are copied into your spellbook. Your first turn, and you already have all the spells they had. At the basic level, up to level 3, at the advanced level, up to level 4, and so on. IMHO, that's when the skill would be useful, especially for mage heroes.
Or give it another function: so that the one with Eagle Eye can see what's in the opponent's spellbook. A good advantage in battle. For example, on the expert difficulty, it could show the elemental upgrades.