Given the critical and creative success of “Mr. Robot,” one would be forgiven for hoping USA’s next high-profile offering, the sci-fi drama “Colony,” would be similarly bracing and mold-breaking. “Colony” does have a few things going for it, most notably “Lost” veteran Josh Holloway as the patriarch of a family in post-invasion Los Angeles. But in general, this series is frustratingly patchy and generic — unwilling to grapple in any consistent way with the moral and political implications of its premise — and key elements of the story remain disappointingly underdeveloped. Pride of place is given to characters and relationships that don’t have much depth, despite the efforts of a capable cast and occasionally arresting action scenes. Like an alien shape-shifter, “Colony” keeps trying to morph into a fairly standard cop show with some espionage elements. In a stumbling effort to create enigmatic mysteries, it just ends up being vague.