In fact, Owl Rangers were not the only ones who could use Beast's Eye. Any Ranger with a beast companion could use it; Owl Rangers simply used it more often. Owls had a broad field of view from high in the sky, and as flying pets, they were extremely fast, allowing them to survey the largest possible area within the spell's limited duration.
The Nightstalker troops also used it sometimes. In particularly dangerous areas, they would send their feline companions in under Stealth, then use Beast's Eye to share their pets' vision and scout the area. Other Rangers rarely used the skill.
Training in pet-related spells also tended to emphasize different things for different Battle-Pet Rangers. Skill priorities and training intensity were arranged according to each battle pet's traits and intended role.
While the Owl Rangers were using Beast's Eye, Sylvanas ran all over the place with six Frostwolf Rangers. Since the spell lasted quite a long time, Sylvanas and the others would sometimes stop somewhere to observe for a while before moving on.
Yu Lin Bloodhawk did not follow her aimless running around. He stayed where he was and waited. If he wanted a clear understanding of the terrain, he could simply use Beast's Eye and make a circuit of this little plain. He had an owl too. What terrain would not be plain to see?
He felt that owls were the best battle pets for commanders like Alleria and Sylvanas. Yet they insisted on having worgs, and even the Farstriders Commander wanted one. He could never understand what was so good about them.
Still, he really did not like the high elves' hawkstrider mounts. They were fine in every other respect, and their feathers were beautiful, but they bounced far too much and were not steady at all.