Spoilers for Spider-Man: Homecoming to follow.
Yesterday The Wrap reported that Zendaya, officially cast as "Michelle" in Spider-Man: Homecoming, is actually playing Mary Jane Watson, Peter Parker's most significant love interest. The internet had a lot to say about it, with many people complaining that a bi-racial actress without red hair would be playing one of comics' most well-known gingers. Others wondered why this was even a reveal, and looked back at Star Trek Into Darkness and Spectre to prove that holding characters as reveals is a bad idea. That's a good question: why would Marvel hold back Mary Jane as a reveal?
Well, first things first - my sources aren't convinced she's "Mary Jane," but I have been told in the past that she's playing "MJ," the abbreviation by which Mary Jane often goes. This means the name "Michelle" wouldn't be a lie, and that Marvel Studios wouldn't 100% be erasing Mary Jane's red hair; this is a twist on the character. So if Michelle's middle name begins with a J, you know this will be the case. Of course it's possible that my source just knows her as "Michelle" because that's what she's called on set, but I had heard about this before the name "Michelle" was even made public.
As to the question about the fact that this is a reveal: that's easy - it always was. Fans who are upset that Mary Jane might not be a redhead in the movie are surely expert enough on the comics to know that Mary Jane Watson was herself a big reveal. Aunt May starts trying to set Peter up with the unseen Mary Jane as early as Amazing Spider-Man #15, and it becomes a running gag that he continuously finds reasons to not meet the girl. Peter assumes that any girl Aunt May wants to set him up with is a dog, and besides he has plenty of girl trouble already in his life. MJ doesn't show up in a comic until #25, and her face is obscured:
It isn't until issue 42 - two years after she is first mentioned! - that she made her famous "Face it tiger, you just hit the jackpot" appearance... which was the final panel of the issue. That's how big of a reveal it was.
How do you pull off a reveal like that today? You can't - the second you cast someone as Mary Jane everyone in the audience knows who she is. But what if you want to have that same sense of discovery that readers had in 1966? What if you wanted to surprise people in the same way, without resorting to a cheap Khan or Blofeld reveal - ie, the reveal only has meaning for the audience, not for the character?
This is how I would do it, and this, I bet, is how Spider-Man: Homecoming is doing it (I do not have any real knowledge of how this story goes in the movie, I'm simply making an educated guess here):
Introduce Michelle. She's kind of frumpy and dresses down. She's not ugly by any means, but she also doesn't catch Peter's eye because the more conventionally and obviously beautiful Liz Allan is running around. Michelle doesn't seem like a fashion plate, she seems kind of like a nerd. Her relationship with Peter, as we saw in the San Diego Comic-Con footage, is full of bickering and sniping. Peter is off chasing the prettiest girl in the school... unaware that the actual prettiest girl just doesn't do her hair or put on make-up. He doesn't realize that the girl who meshes best with him is the girl in the oversized jacket who lobs zingers at him (the kind of zingers he might lob as Spider-Man). Until one night...
Yup, the titular homecoming dance. We know it's happening - a sign for it was seen in the SDCC footage. John Hughes has been namedropped as an inspiration for this movie, and there's a famous 'twist' in The Breakfast Club, in which Ally Sheedy gets cleaned up and is finally recognized as 'hot.' Imagine a scene where Michelle shows up in a great dress, hair all done, in make-up, and says that all her friends call her "MJ." That's how you make the reveal matter to both characters and audiences.
Again, I have no inside knowledge about that element, just that Zendaya is playing someone named "MJ." That's all speculation.
The red flag here is that the Ally Sheedy twist in The Breakfast Club fucking sucks. I hate that twist. I think Sheedy is hotter when she's a weirdo. Cleaning her up violates what makes her special. But check out some set photos of Michelle - they're not dressing her as special. She doesn't have a style. She's dressing down, very conspicuously so. And if it's her decision to get glammed up for the dance: good! I think people do look hotter when they put some effort into how they look. It's not a trope, it's not a cliche, it's a simple truth - find clothes that fit you well and get yourself a decent hairdo and wash your face and you'll be shocked at how much better you look. Take it from me, I do it about two or three times a year and everybody is amazed! If I can do it, so can Zendaya.
So that's my guess as to why this character is a reveal. I agree it's kind of a bummer that the info got out there (and yes, we ran it as well. Welcome to the arms race that is online writing), but I think the reveal can still be fun in context.