The great thing about X-Men comics is how each character possesses a unique mutation that makes them special. It's the intermingling and opposition of these unique power sets that make each battle so intriguing. The powers represent an integral component of each delicately crafted personality and delineate characters that can thrive for generations.
That uniqueness highlights a central theme of the X-Men mythos: the chaotic and inimitable process of random mutation. Presenting evolution through the prism of individual perception builds a powerful allegory that has drawn in readers for over 50 years. That's why it's so important that no two mutants are alike... at least until a writer runs out of gas and throws in the towel.
Over the years, X-Men writers have hatched some amazing characters and then followed them up with knock-offs and carbon copies that are in a word... redundant.The expansion of the mutant population has at some points inferred the existence of thousands of mutants, so some overlap is inevitable, but it's no accident that some of the worst offenders mimic Marvel's most popular characters. Whether they be clones, descendants or just sloppy writing, these are the most redundant X-Men characters of all-time.
First Appearance: Uncanny X-Men #327
X-Men writers love to have a villain change sides and join the X-Men. Sometimes they write an elaborate arc to explain why a character would shift his or her morality so drastically. Other times they just quickly whip out a clone.
Joseph is a Magneto clone that writers desperately tried to make a sympathetic figure in some truly un-engaging story lines. The main difference between Magneto and Joseph is that Joseph sucks.Rendered Redundant By: Magneto
First Appearance: ROM Annual #3
Wings are cool. Wings look rad. Warren Worthington III (aka Angel) is one of the original X-Men, because he has cool, feathery wings. There was hardly any reason to give Josh Guthrie cool, feathery wings before killing him off. The main difference between Icarus and the original incarnation of Angel is that Icarus is a much better singer.Rendered Redundant By: Angel
First Appearance: New Mutants #98
There was already a blue-skinned, female shape-shifter in the Marvel Universe, but that didn't stop Fabian Nicieza and Rob Liefeld from creating Copycat. Allegedly, her powers are more in-depth than Mystique's, allowing her to imitate a person on a genetic level... nice try guys. Sadly, Copycat is a copycat and not a very popular one at that.Rendered Redundant By: Mystique
First Appearance: New Mutants #99
There are lots of Wolverine knock-offs with claws and winged haircuts, but Feral is especially offensive in that she manages to rip off Wolfsbane at the same time. Unlike Wolfsbane, she's not a werewolf, she just looks like one wrapped in anatomically impossible neon clothing. She also has a prehensile tail which is taken straight from Nightcrawler's playbook.Rendered Redundant By: Wolfsbane