An right now you sound like one of the people against X-23 and She-Hulk being in the game bc on the surface they have the same powers as their male counterparts, but luckily the developers were alot more creative than that and did plenty to differentiate them.
No. Not against. But skeptical? Yeah.
As I was also skeptical with Akuma and Vergil, I liked Akuma before MvC3, so I didn't really worry about his inclusion. And I knew Vergil had plenty of cool powers and abilities to be explored, so the concern was on Capcom doing it justice.
With She-Hulk, I knew about her fun personality and that they could explore it and they did it well, but she is among my less used characters. I just don't like playing with her. X-23, on the other hand, is one of my most used. She just feels so stylish and dangerous, but I was certainly skeptical about her inclusion, since all the intel I had about her was what we got with the X-Men Evolution cartoon, and she just seemed like a Wolverine clone (which she is), with not much to add.
Do Storm, Strange, Phoenix, Doom, Magneto and any other flight/projectile characters play all the same? No they dont. For one, none of those characters have super strength and are known for their close combat melee style. Thats how Carol is. She's a fighter who uses her fists, rush attacks and her strengths to throw her enemies and thigns at them. None of the characters you listed quite play like that. She has the super agility to make her combos and regular moves a bit more acrobatic. She also has super speed so she wouldnt be as slow and floaty like Strange and she's not fragile like Jean. She has the added bonus of being an energy based character with the ability to absorb energy attacks, which would be great for counter attacks (in addition to her cosmic awareness and sixth sense). She is able to rechannel absorbed energy in the form of photon blasts and beams.
Ms. Marvel is a character with a ton of potential as she has alot of abilities and powers under her belt. Nova is the only character I would say is remotely close to her but even he isnt quite an adqueate replacement as she can do so much more than what they've put with him
This is a description. With this, I can see her possibly working out.
When you tell me her powers are simply based on flight, super strenght, projectiles and other things that many other characters already have, you're being too vague. Specially since I don't really know the character.
Then again, if I could pick between her and a character with more variety to her attacks that wasn't already explored in this game, then I'd pick the other character.