If Raimi really wanted to do something with CGI, he had Venom. Venom is a lot harder to do than Sandman or Hydro-Man. Carnage would be even harder to do than Venom, but of course you can't have him without having already done a Venom story. Lizard isn't that hard with CGI, neither would Mysterio. But Raimi wanted Sandman because Raimi wanted Sandman...no other reason. I think its funny that he once said he picks villains that further the plot yet he picked one of the villains that did the least with an emotional connection. Hell, even Jackal would be more of a Parker/Spider-Man connection lol.