Sony wants to do a Venom movie. There is nothing wrong with the idea of doing this movie. While I don't think this is a bad idea, there are indications that this idea will be badly executed.
For one thing, the same producers that were behind the bad Amazing Spider-Man movies will be attached to this movie. Remember, those movies made so little money Marvel had to step in to make him awesome again (just how awesome we will all get a chance to see this year in Captain America: Civil War).
For another, Venom will apparently be divorced from the Spider-Man franchise. So, Venom will just be some guy with an alien parasite as a costume, instead of either Peter Parker's journalist rival Eddie Brock or Peter's former bully Flash Thompson? Both those guys are attached to the Spider-Man mythos, and are integral to Venom's origin and motivations (both the costume and the people in them). Given Hollywood's recent terrible record with origin stories I'm willing to bet Venom's will be this: a lightning strike will spill unknown chemicals onto Dr. John Generic Smith while he's wearing his black pajama onesie, endowing the costume with intelligence. That equals boring.
They are also planning a franchise around him. He is a one-note psychotic villain with Spider-Man's powers. He's going to look and sound like grimdark Spider-Man. That equals double boring. There's no franchise to build around him.
Fortunately for me, Venom was never a compelling character, so I don't particularly care if this movie will be good or not. But for every bad movie like this that gets made, there a good movie NOT getting made. That depresses me.