And Quesada and co didn't bring up Ditko at the time (I'll take your word since I'm not a OMD Kremlinologist) probably because outside of one obscured figure, he never drew Mary Jane. It's probably the same reason they never ask Marc Silverstri his thoughts on what they are doing with Venom since he drew his arm in Web of Spider-Man 18.
I don't know what Ditko thought about Mary Jane, and I wouldn't presume to guess, other than to say that it does seem that leaving Spider-Man was a painful experience for him, since he did further work for Marvel but refused to ever draw the character again. So I doubt he was keeping up with what happened in the book post ASM 38.
But here is what John Romita Sr had to say: "Stan wanted Gwen to be Peter's girlfriend...he started using Mary Jane to make Gwen jealous of Peter. Gwen would have never noticed Peter if Mary Jane hadn't started throwing herself at him."
And Gerry Conway: "Glory Grant was a strong and sexy female. It was my intention she would have a romantic relationship with Peter, but it never went anywhere."
"During my second run in the late eighties I was more interested in the secondary characters because I had sort of moved on emotionally from where Peter was. He was too happily married for me."
Marv Wolfman: "I had Peter propose to Mary Jane in my first issue to end their relationship. Peter always worked better when he was a loser who worked hard. I didn't think he should be dating someone who looked like a supermodel."
Roger Stern: "Spider-Man doesn't seem like Spider-Man anymore. It all seemed to fall apart when he got married. I'm not saying I would have never married Peter off, but I wouldnt have paired him with Mary Jane. She worked best as a spoiler, an old girlfriend who would occasionally appear to mess up Peter's life. She and Peter really cared about each other and they had some good times together, but they were like oil and water. I never thought the marriage would work. When I wrote Hobgoblin Lives Peter seemed different to me. It was like running into an old friend that you knew in college. He had changed and wasn't as happy as he used to be."
Tom DeFalco/Ron Frenz: "Our original plan was to take Pete and Mary Jane through all the steps of the engagement process. They were going to set a date and Mary Jane's past would come back to haunt her. Her sister would contact her right before the wedding and give her a chance at reconciliation. She would use that as an excuse to run away from Pete because she was still afraid of being tied down. Pete would be out fighting super-villains and barely get to the church on time. Harry would meet him on the steps and we would have this silent sequence where he gives the wedding ring back to Pete. As Harry walks away, the ring drops out of Pete's hand and the scene ends with a long shot of Pete standing all by himself. Anyway, Jim Shooter decided that Pete and Mary Jane would actually get married...I was offered the chance to pencil the wedding issue, but turned it down because it didn't feel right to me."
David Michelinie: "I actually wrote the wedding issue--but it wasn't my fault! I didn't think they should actually get married. I only wrote the script...Jim Shooter wrote the final plot."
"I wasn't keen on the marriage from the start, in fact I was plainly against it. I think it diminished the identification factor with the reader. I thought it was a big mistake, like when they decided to have Peter graduate from college. It changed a basic aspect of the character, but there was nothing I could do about it."