Which units would you replace in the Sylvan castle?

You don't necessarily have to remove magic, but in that case, the Elves would have as many as 3 casters, and any Academy would be envious. And the spells would be chosen wisely. For example, against Dungeon, the Fairy would always choose the Fist spell, and the Dragon would never use Chain Lightning if the enemy has only one stack of units, and wouldn't waste Ice Ring on a small unit. Then the Elves wouldn't be a weak race, that's for sure.