I wonder if we'll get another Green Goblin in the second film, with possible hints in the first film (ala Batman Begins and the Joker Card). William Dafoe was good as Norman Osborn, but the Raimi Goblin costume is silly and now, dated. I'm thinking something like the comic-allowing us to see some expressions this time without giving away the identity. Or maybe something like Harry's outfit in the third film.
I think they should have face-paint (with accessories like skullcap and maybe ears). Go for a "Joker warpaint" theme that makes his face look rubbery and goblinesque but still able to emote. Kind of like "Fear Gas Batman"
from Batman Begins.
In the comics, the GG mask has always had an unnatural facial cling anyways. It's just a practical version of the same thing.