Peter and Gwen's personality has always matched. and look at her fanbase? they all consider her "perfect" and put her on a pedestal as the most ideal love interest for peter. Lol don't tell me what i'm thinking.. my first introduction of gwen was the comics.
Nope. Look at the beginning of their relationship. They were constantly at odds. Even though Gwen was studious, she also loved to hang out and party. She wasn't as extreme as MJ was said to be (Even though this was never actually shown- but since she was running with Harry and Harry did drugs one can suppose that she indulged a bit herself) but she certainly was never presented as being timid. Please point to a story that suggests this. Since I have every issue, I'll be happy to verify. Then later, Gwen was getting more involved in activism; student protests, environmentally, politically, and she would come down on Peter for his lack of interest (Even though we know why he couldn't spare the time) She was constantly wondering where he was running to and why. So they weren't perfectly matched. Or no more so than any couple who while being different, still have a love and respect for each other. It was the same with Peter and MJ.
And Gwen was hardly perfect in the flawless sense. She made mistakes, had a hot temper and was quick to belt someone who pissed her off. If anyone who's actually read the comics suggests she's perfect, it's as in she's the best choice for Peter. Which I agree with.
black cat is easiest to write because she's never a serious love interest. She's mostly just there for action and for straight men to fantasize about... (and yes, i'm saying this as she's also still one of my favorite spidey characters (and i currently own every issue she's ever been in). She's easy to right as she always comes and goes. She doesn't need to be present in every issue.
Black Cat was certainly a serious love interest at one point. Peter was considering a life with her and made many overtures to see to it that it happened. He just ultimately realized that it wouldn't work and he wanted to be with MJ.
As for MJ, I'm no writer, but I think as a reader it was easy to see that her boring-ness came from the fact they gave her nothing to do...
Every character is boring for that reason. There is not a one character that is inherently boring. It's only the way that the writer presents them as being.
But some characters have more dramatic punch than others. Based on who they are, their background and environment they can have a lot or little built in drama.
I'm saying that in the case of a human character involved with a super human character, for the relationship to be interesting beyond the "chase/ will they-won't they point- the human character has to bring some interesting baggage to the table, that rivals the hero's drama. While Peter is out constantly risking his life, his wife looking for acting gigs, possibly being a hostage, maybe being attracted to another man, and maybe getting pregnant is interesting for but so long. With Gwen, there was a lot more potential, even though the other stuff is there as well. It's just that the writers didn't have the vision to see it.
MJ was a public eye character. I don't see how that creates less drama then gwen? who was low-key compared to that. Mj had death threats, media attention, kidnappers, and the contrast between her living a very public life... and peter living a very private in keeping his identity created much more drama. It's when they stripped her of all her media related stories is exactly when she got boring. coincidence? i think not. It's also the reason why MJ and peter's relationship lasted more than twice as long as peter and gwens.....
MJ being the "public eye" character was solely because Marvel pushed her that way. They made the wedding a media event that went beyond the comics, having actors play them at Shea Stadium, home of the then World Champion Mets. They published artwork focusing only on MJ. Toys, etc. She was the love interest in the multi-billion dollar movie franchise. They made stories that centered on her and even whole comic book titles. They didn't do any of that with supporting characters (non-super ones at least) when Gwen was around.
And while yes, the MJ relationship lasted longer, Marvel had constantly been trying to jettison it. They've made no less than five attempts to end the relationship. But they knew they couldn't kill her off as with Gwen. And mind you- there was plenty of public outrage with Gwen's death as well. Sales dropped on the book.