Even if it’s just a really cool looking skin, it’d be a neat idea to have “legendary pets” Rangers can quest for. Nothing so intense as a legendary weapon or armor. Just a few a simple quest lines that maybe gets into some cool GW lore. Maybe a few collections thrown in there.
You must put together a collection to offer the legendary pet to persuade them to join you. You have to impress them by defeating powerful enemies. You have to purify a corrupted place or retrieve an ancient treasure.
Then you can have a Kirin as a companion, or a Phoenix. Something neat like that. Maybe not much more powerful than a regular pet, mostly just a cool aesthetic.
If nothing else “Legendary Tamer” could be a future elite wherein the ranger could summon or swap in a powerful “legendary creature” they’ve made some kind of pact with.
Not expecting this to happen, just a fun idea.