You know a lot of people say they want the Billy Cubs swinging device but realistically speaking how the hell would that work?
Well its logical if set up and explained well enough, I dont know if we will ever see him proper DD swinging about, but Id like it there to allow him to do some partial swinging, grappling, weapons etc.
The best way to do it would be further down the line, Matt is clearly not going to be able to invent this, but in the Marvel universe, Hawkeye in avengers 1 has that grapple device on his arrow when he jumps off the building. That perfect right there inside the billy club rather than an arrow, so there just needs to be a set up where he has a contact with Shield or some character from shield, or a character that has clearly got the brains to invent tech like that.