I agree with some people here that not all of Spider-Man's rogues need a sweeping, generalizing change to become viable. Some of them just need tweaks, or others just need to have an few more memorable outings.
Some of the ideas about Black Tarantula are interesting, although the problem with B.T. is that he, like many things of the late 90's, suffered under the weight of some of the problems of that era. He was in Spidey books during the 1-2 years that were between "Clone Saga" and the "Reboot", which are hardly fodder for essentials. It had NINJAS for god's sake, and excuses for team-ups with the X-Men. B.T. also reminded me of a pretty straight rip-off of Bane; 7-foot tall Hispanic thug who can easily maul the hero and yet has a sort of chilling cunning to his ways, and a conscience that exists to let him leave the hero alive for plot convience. Robbie Robertson was his "old friend" or something, sort of like Tombstone was, but this connection was never revealed (Robbie, like almost all of Spidey's supporting cast, has gone into limbo with Peter being a teacher, with no new supporting cast members to replace him. I'd have thought that teaching at a high school would provide fodder for tons of new supporting faces, like fellow teachers, superintendants, the principal, notable students, but what do I know? I don't get paid 5 figures an issue). That's not to say that Black Tarantula can't be built up as a manipulator, as that was what he did before; in fact, DeFalco spent almost TOO MUCH TIME building him up, with clues that often contradicted each other. True, Marvel COULD simply find a way to learn from their mistakes with some characters, but Marvel isn't in the business of learning from mistakes. They shelf mistakes, pretend they never happened and then truck out those same mistakes again, maybe 2-5 years later with some new bows and technique, and hope it flys THIS time. Sort of like when The Shredder would sic Bebop and Rocksteady at the Ninja Turtles, no matter how many times they failed.
I wouldn't mind someone amping B.T. though; Spidey could use a "Bane" figure. I'm all for replacing the much-overused Norman Osborn.
Some repeated ideas:
Hydro-Man: In my very first fan-fic, I had him find a new "purpose" by wanting to become a sort of "extreme terrorist" who was angry about water pollution and sought to merge with the ocean to make the world pay for it. The problem was that despite his new ideology (which won him the support of some extreme "eco-protesters"), he was still a thug who wouldn't care what his power fluctuations did to the ocean itself.
Scorpion: The basis of my longest fan-fiction about 2-3 years ago, my idea was to strip away what ruined him from the start; the "killer instinct" that reduced a once clever P.I. into a raging thug whose anger could always be exploited, who had no new ideas, and whose only advantage was a slight physical strength advantage. In the story, he used head-meds to ease his "insanity" symptoms, which made him more cold and calculating mentally. He was able to use the body of someone stronger than Spider-Man with the brains of an expert detective for a very dangerous combination. And of course, the mechanical tail. The point is, Scorpion could have been Spidey's "opposite match" years before Venom if he'd been handled a little differently.
Shocker: I see him as a low-level Techno, someone who has a "knack" for building gadgets out of rubbish, which is how he made his "vibro-shock" units. His speciality is building gear that revolves around wave vibrations, so we'll stick with that. I see him as a shrewd "robber" baron who really isn't out for revenge or power, but to make a dishonest buck. Take a bit of an example from some of Flash's rogues, and maybe have him lead a very small band of "masters of evil" who basically run around other states and commit robberies. Shocker's taken enough beatings that he may want to assemble a loose knit "rogues" band (especially after he was just captured by the Young Avengers).
Mysterio: subject of a fan-fic I haven't written yet, a good gimmick for him could be to want to drive Spider-Man "insane" as a sort of "act" to prove that everything Spider-Man stands for is nothing but an illusion...and Mysterio is the Master of Illusion.