The legendary fish might be used in Inside the Belly at a later date... I believe they've done this before, added Leg. Fish and then gave them Inside the Belly later on. Still, I agree, hopefully they make a few more fish useful for something. Erm, train of thought, They added new Torques for crafting... maybe they'll come from Inside the Belly... while I personally hope not cause I don't have high enough fishing for it, maybe?