As if epic and rare fishing poles weren't enough to catch fish and slowly level up fishing, the next expansion will introduce an artifact fishing pole called the Underlight Angler, with its own traits and special abilities. One of the biggest new features of Legion will be powerful Artifact Weapons that we can level up and modify, and each class and specialisation will have its own weapon. Adding an extra fishing pole using the same mechanics certainly sounds like a good idea.
That's mostly because fishing in WoW is one of the most tedious things to do. It's slow, boring and, besides catching a few cool rare items, it doesn't really have any purpose. But most WoW players are completionists and care about achievements and mounts, so they level up fishing anyway. Wowhead made a video showing all the completed models:
As the current alpha build of the game shows, we can modify this special fishing pole to be able to walk on water, teleport to the nearest fishing node, become a fish (alright) and catch certain fish types. Sounds great!
Fishing is the only secondary profession where a piece of equipment is required to do the job, but still, maybe Archaeology would be a lot more fun with something similar.
Top image via Battle.net