I have a couple of new ideas for the game.
I think you should be able to exchange dragons (maybe even legendaries), runes, wood, fish, iron, Odin coins, item packs, collection materials (including things from Johann/legendary dragons) and raw/polished amber with other players, similar to the Global Link in the Pokémon games.
You should also be able to breed dragons together. This would make it easier to get rare dragons, such as the Sweet Death. Maybe you could even crossbreed different species to create hybrids, like in Titan Uprising.
I would love it if Ludia could add these ideas in a future update!