My first reaction was nope. Too late now, can't make a Labyrinth sequel without the original Goblin King.
I do still think this but I am really curious as to where they take this in terms of plot lines and characters. Will they bring Jennifer Connelly back? What about Toby Froud? They need to at least have the original Sarah I think.
Or maybe they just need to leave it alone and not ruin it 