I don't think we've seen the last of Gao. If Daredevil, (and Elektra presumably) were spared from dying by simply being in the dust of the Dragon bones then perhaps Gao will return too. I definitely think they should merge Luke Cage, and Iron Fist into one show. They have a full, and great supporting cast, and I would definitely be excited to see some episodes spotlighting Wing, and Knight. They have a great premise already set in place for it.
Imagine they go with a Luke/Danny buddy show where they are "heroes for hire" just like the book. Danny moonlights as Daredevil until Matt returns. He decides to stick with the vigilante life, and dons a costume similar to his comic look. He somehow loses a large chunk, or all of his fortune steering him into a partnership with Cage, and the ladies where they open up a Jessica Jones type business with Dawson serving as team medic/voice of reason. Maybe they get funding from Stark, or SHIELD. Or maybe they form an agency to directly oppose Diamondback, and (Gao?) who's returned to Harlem to form a super mafia type group of his own to fill the vacuum left by the Hand. Daredevil, and Jessica continue their own respective series with an occasional crossover or guest appearance. Then they could all just reunite for the eventual season 2 of the Defenders.