Hmm... I'm not really sure how many people would really care that much about seeing people like Robbie, Betty, Flash, etc. less. I mean, they've hardly been in the book for the last few years and I've seen maybe two or three people regularly complain about it, and a few people who would like a check in with them but don't care too much. It's only the few main characters like MJ, Aunt May, Black Cat, Harry, etc. who are more in demand, and even then, I'd say a writer could pull off well-loved storied with only May and MJ around.
As for rogues gallery, I think we agree. The problem is, most stories don't do anything interesting or new with the established villains, which is why I made that point. Like, there's a difference between using Ock in Superior Spider-Man (great character development) vs using Osborn in Osborn Identity (basically a completely useless story).
I think JMS did streamline the cast quite a lot. Even if we do include Iron Man (which was only really in the latter half of the run), the main cast was STILL just MJ, May, and Stark, in addition to Peter. Sure, other characters made appearances here and there so the world didn't feel empty, but those 3 were the only real recurring characters in addition to Peter.
Personally, I think focusing on a few key characters and giving them the attention to meaningfully develop is a lot better than having a large cast just because. After all, supporting cast stories will almost always be the "B-Stories" in ASM, which means they have very limited page space. That's why I think that is the best approach. I mean, in how many stories has JJJ's or Robbie's (or hell, Philip Chan's - if that's what his name is) personal life ever had an real impact on the story? Now, contrast that with how many times MJ's or Aunt May's personal life has had an impact. Just my opinion though.
I think using new (or non-stereotypical "Spidey") villains works better for both new and old readers when done well. New readers don't have to puzzle through obscure references, but old readers are also treated to something new. Of course, as I said before, old villains have their place as well, especially considering that cluttering the Marvel Universe with more superpowered beings may not be such a great idea, LOL.