Yes, because then it'd be a shock when they met. But Betty and others seeing MJ beforehand was supposed to build her up in the reader's mind. It's like, hey, they think she's so awesome, Peter is such a blockhead for not wanting to meet her. But it's still using supporting cast to hype her. And the thing is that it's not a bad thing. Watched some NCIS episode the other day where the show's regular cast totally hyped a new character to the audience. It's the fact that because Carlie was supposed to be a love interest that suddenly makes it a bad thing to do.
They were both love interests, even if MJ was a spoiler. She'd still have some sort of romantic drama with Peter to complicate things with Gwen. Difference is that Carlie was working her way up to being an actual girlfriend, which I still don't think they shoulda done because the female love interest always loses something in the trasition.The circumstances behind MJ's introduction and Carlie's introduction were radically different. You can say they were selling these characters to the audience (which, of course they were, but what people are trying to say is that they did a crap job selling Carlie to the audience because OMD), but they were meant to fulfill different roles.
I'm not arguing whether or nor MJ was supposed to be Peter's "ONE TRUE LOVE."MJ wasn't supposed to be Peter's "ONE TRUE LOVE." She was originally presented as a ditzy party girl who didn't give a crap about anyone not named Mary Jane Watson. This is why her showing concern at the end of "The Night Gwen Stacy Died" (which was about 7 years after MJ's "Face it, tiger" introduction) was seen as such a shock. (Sure, in retrospect and with much deeper characterization these days, it shouldn't be a surprise that she exhibited grief over the death of a friend and concern towards the boyfriend of said dead friend. But characterization wasn't particularly deep in that era.)
They didn't start dating until Big Time, something like three years later, and lasted a good four years in total. I don't know that that's the first available possibility.With Carlie, it seems like (speaking generally here) "this is Peter's girlfriend now" was the order of the day. And given the comments Slott has made, they knew the audience would hate her because they would hate anyone after OMD. And they just sort of went with it. You can make the argument that she wasn't given a fair shake. That Marvel tossed her aside at the first available possibility. But it's important to note that Carlie was an active member of the supporting cast for more issues than Gwen Stacy was a living member of the supporting cast.