You can get a lot of the powerful Enemy Skills early by preparing for the battles. I always get Beta before I go through the Mithril Mines, by using the Elemental + Fire combination, and forcing the Midgar Zolom's attacks. You can get Aqualung before you enter the Golden Saucer, by hugging the east side of the Golden Saucer desert area. With spells like those, you won't need KotR, and they're a lot cheaper MP wise too.