They could always ressurect the Ghost Rider series by doing a crossover mini event where he kills Memphisto. Especially now that Dr Strange won't be sorcerer supreme...
Unless some cool writer takes over and screws all this, has Dr Doom become the new SS, get the evil Illuminati together and start forming an army with Namor, Penance and the Hood, but Osborn stands in his way, and he recruits Spidey but in order to do so he does him the favor of taking out Memphisto... I think that would be a team worthy of the possible new avengers team of Odinforce Thor, Shiney Cap, How many times are you going to get upgrades Iron-Man and maybe Wolverine..
But spidey you know.. wouldn't really be evil, he still wouldn't kill people, just fight for Doom. Come one! It's doom, we all love him. No but seriously wouldn't it be awesome to see Osborn's Thunderbolts take on Doom's illuminati? I still think Osborn would somehow win even though the Dark Illuminati is crazy powerful.. especially now that Bullseye doesn't get affected by psychics (bye bye Emma!)