The Aqua Rod requirement is currently an intentional design choice because the entire progression system (rod XP, talents, abilities, breeding progression, quests, and more) is built around it. Using a vanilla fishing rod would bypass many of those systems.
I'm also planning to add a custom crafting recipe for the Aqua Rod in a future update, so players will be able to craft their own rod instead of relying on commands or admin distribution.
That said, I completely understand the appeal of using the standard Minecraft fishing rod, and I'll definitely keep the suggestion in mind for future updates.
Thanks again for taking the time to leave a review and for supporting AquaBreeder!