this feels like you wrote this ten years ago...most of the characters you're comparing are dead, never used, or no longer have ties to the X-men
 to name a few examples here....Quicksilver, Husk, Mercury, Firestar, Mastermind, Lady Mastermind, Prodigy, Strong Guy,  Chamber, Nightcrawler, Blink, Boom Boom
 so right there is nearly half of your list
 

Quicksilver has had very little to do with the X-men for a long time, if ever, yeah he's Magneto's kid and played a direct role in House of M but other than that he's more known as an Avenger than an X-man

You made me laugh. I mean, actually laugh.  
Firstly, Emma Frost and M have vastly different powers. Frost's are telepathic, with her secondary mutation being the whole 'turning into diamond' thing. M, however, has very little telepathic power, her main abilities being flight, strength, and near invulnerability. Both are highly intelligent, but they hardly fill the same role.
Most of your points are really flawed (not to mention Blink and Nightcrawler no longer exist in the same dimension). I agree with the first somewhat, but when you get to the 'Brooding Dudes' subject, you went waaaay off track.
Firstly, brooding male characters are by no means a new thing to the X-men. Also, the fact that you left out the original whiner, Cyclops, was really kind of...well, sad. 
'Bulky Guidos' is really more or less easily mixed in with 'Giant Sized X-men', in that your point is the same for both (except for the whole 'straight man' comedy thing). Also, might I point out that Rockslide's powers are nothing like those of Strong Guy. Rockslide is MADE OF ROCK. 
I chose to skip 'Pretentious and Elf-like', because the flaws with your argument seemed to apparent to warrant mentioning.
Teenage Mutant Ninja Genius was closer than I'd like to give you credit for, but still way off the mark. Cypher is omnilingual, while Prodigy just knows things. Granted, he knows ALOT, but if he hadn't happened to absorb the ability to speak...oh, I don't know, German, while he had his powers, he'd have to learn it like a normal human being. Cypher knows it, can speak it, read it, end of story. The two do NOT occupy similar niches.
Do NOT compare Sunspot to Hellion. Sunspot, while rather headstrong, is a genuinely caring, kind and compassionate person, whereas Hellion hasn't displayed the ability to show kindness since Sophia left, which is a long time. 
Your 'Masters of evil' point never needed to be made. Mastermindis called Mastermind because she comes out on top, therefore getting to inherit their father's mantle and name. End of story.
Loa destroys anything she phases through, how is that comparable to Cipher's power? I mean, there's the phasing element, but Loa's power is solely destructive! 
Magma controls the very molten core of our planet, and is able to transform herself into living lava. Firestar...emits microwave beams or something. It's been a long time since I read her miniseries. The two aren't even similar in terms of personality!
If 'someone has to go', it would be Mercury, because she's living liquid metal, whereas Husk can be anything she could want, at any time. You're only comparing them by operating under the assumption that Husk normally operates as living liquid metal. 
Colossus and Warpath, on top of being incredibly dissimilar, don't share very similar powers, nor do they even fulfill the same function. Colossus is ORGANIC STEEL, whereas Warpath is strong and very, very hard to hurt.
In closing, I'd like to remind you that Quicksilver is neither a member of the X-men nor a resident of Utopia. Hell, Magneto lives on Utopia, you can be pretty certain Quicksilver isn't going to want to settle down there any time soon.

I agree with the OP.  I don't think its the technicalities that are being overlooked, but moreso...hey Mercury is metal but Husk can already turn into metal.  I think the complaint is that the distinctions are insufficient and the overlaps leading to redundancy.

I disagree. ALL the X-Men/Mutants are redundant, ONLY, Wolverine is relevant or needed, or unique. Kill off the rest thanks. 

I thought this was a clever post.  Honestly, theres only so many powers to go around yknow?

"I disagree. ALL the X-Men/Mutants are redundant, ONLY, Wolverine is relevant or needed, or unique. Kill off the rest thanks.  "

I truly pity you you sad sad little movie gower

There are so many powers that can be used like turning into soap or something like that... I swear the elemental, psychic, superhuman powers are overused these days.

Interesting Blog

From an editorial standpoint, Decimation occurred to dwindle the mutant population to a select few, eliminating their quantitative dominance in the growingly generic field of new characters.  However, the X-Men's cast still seem to contain characters with shared identities--that is, they share duplicate roles, powers, and even general personality traits.  Sometimes this can result in interesting relationships (including the Mastermind sisters who are listed below as well as Emma Frost/M in Generation X) but Utopia has really brought the dullness of the mutant population to light.  With such few mutants left, each character has to be individual and remarkable in their own right or the 198, Utopia, and the narrative set-up of Uncanny X-Men just doesn't work.
 
Here are some of the characters I think should battle it out to strengthen the larger mutant ensemble of the X-Verse:
  
Battle of the Explosive Babes - Dazzler or Jubilee or Boom Boom?
Fans and creators alike have argued that Jubilee was X-Men writer Chris Claremont's tabula rasa version of Dazzler, whose character was already largely defined by her groundbreaking solo series while Jubilee and Boom Boom have often bonded by their uncanny similarities in both power and personality.
  
Colorful Transporters - Nightcrawler or Biink?
Not much to differentiate here but general ability (I know they are used in different ways) and general appearance, but the fact that two of the X-Men's discolored mutants can teleport does raise a few redundancy flags. 
 
Brooding Dudes - Chamber or Rictor?
While their abilities are largely different, both former mutants can be characterized by their ability to brood over various tragic events in their lives.  While their circumstances are different, these dark-haired heroes still fill the same personality role and their similarities may make it impossible for them to ever serve on the same team. 
 
Bulky Guidos - Strong Guy or Rockslide  
These two characters have different visuals, but similar tank status in their respective affiliations.  Additionally, they both are the comic relief/dumb jock of their inner circles and both even are often paired with their own "straight" man (Madrox and Anole, respectively).
 
Pretentious and Elf-Like - Northstar or Namor  
While one is half-fairy and the other half-fish, these two often-waxed, high browed individuals are infamous for their snark on-and-off the battlefield.  Both share the ability to fly (among their other abilities) and have had trouble holding on to a steady gig in the past decade.  

Teenage Mutant Ninja Geniuses  - Prodigy or Cypher 
Since Cypher's return, he's taken over the role of young genius working on Danger and other "smart guy" projects Doctor Nemesis has no time for.  Both are former New Mutants of two different generations and have a history of being creepy, supportive, and boring in their comic book careers.  

Arrogant Playboys  - Sunspot or Hellion 
Both are from different junior X-Men teams and both have the ability to snag the ladies.  While Hellion's been cut-off since his self-titled mini-series in 2005, both men have been raised with a silver spoon in their mouths, spending their parents money on their mutant friends.  

Masters of Evil - Mastermind or Lady Mastermind 
This comparison is only natural and while these two ladies have shown to be able to co-exist and be interesting due to their scathing rivalry, its only a matter of time before one sister comes out on top.  

Unphased Youth - Cipher or Loa 
These two women share the ability to phase through solid objects, although one specializes in covert operations while the other can be a bit more destructive.  However, their general ability is duplicated in an already large generation of students and its only a matter of time when another crossover rolls around and another New X-Man has to turn in their shirt.  

Firey New Mutant  - Firestar or Magma 
Again, two lady mutants from the same generation share similar powersets.  However, one has been occupying her time in the larger Marvel universe while the other occupies her time...I'm not sure what Magma does with her time, actually.  

Maiden of Metal  - Husk or Mercury 
Most people would have trouble differentiating the two if it weren't for their brightly colored wigs on top of their metal bodies.  Someone has to go.  

Giant-Sized X-Men - Colossus or Warpath 
Warpath is more of a legacy to his brother, the original Thunderbird who debuted alongside Colossus in the 1970's, but nonetheless the two are large tanks in the X-Men arsenal.    Warpath's use had been growing steadily since he joined the X-Men during Brubaker's run, but he has drifted off the radar since leaving X-Force.  Can the younger spirit outshine the iconic if not stagnant Russian tank?

Quickly Catty - Quicksilver or Northstar or Velocidad (Gabriel Cohuelo) C'mon...the similarities are just too much.  Fast, snarky, and the former two even have similar eye-brows.  Quicksilver has so much more relevant history to the X-Mythos but he is also oft-relegated to the Avengers or the removed X-Team X-Factor.  Northstar is an iconic gay figure in the X-Men.  Gabriel is part of an important new wave of mutants and also has newness going for him.  But which one belongs?    

Of course its redundant nothing wrong with it. The x-men have what a dozen books right now u got to stock those books with characters.