Could we see the Green Goblin and/or Doctor Octopus brought into the Marvel Cinematic Universe someday, perhaps in the MCU’s Spider-Man 3?
Spider-Man has such a great rogue’s gallery that there’s a lot still I think to draw from.
As for Green Goblin, he was the main villain in the first live-action Spider-Man and also had a presence, in a different way, via James Franco’s Harry Osborn, in Spider-Man 3.
When asked about those characters showing up in the future in a recent interview, Jon Watts had this to say.