I remember back in the project M days, there was a poll about changing Ganondorf to have more unique moves (which they did) and then use the "old" model to be replaced with Black Shadow. I was very much in favor of that.
With that being said, for the F-Zero franchise it would have been nice to have more representation for them. Having Blood Falcon as the Echo Fighter of Captain Falcon and then using Black Shadow as the more Ganondorf model to be a "semi clone."
However, with the changes to Ganondorf's standard attacks that uses his sword, it now is very unlikely to see Black Shadow being included as that Semi Clone. Personally, I still think Ganondorf's moveset should change to relfect more of his character instead of a Semi-Clone of Falcon.
Also, unfortunately, the F-Zero has been frozen since the GameCube days, so I don't see a focus being put back into F-ZERO.
In the later future, if Smash is ever rebuilt to make major changes, and F-ZERO becomes relevant again, that would be a nice addition and change.