Ok heres how it is.First we're going to talk common sense then we'll we get to speculation/rumours/suspicions.
The fact is Sam Raimi and Tobey Maguire both said in Wizard magazine that the next villain they would like to do is Sandman.
Thomas Haden Church looks alot like Sandman.Just as much as Alfred Molina does for Doc Ock.
Sandman can provide big fight scenes.The Chameleon cannot.Sandman is unique and very different from Green Goblin and Doc Ock.Different is good.The main villain has to be different to the previous two otherwise audiences will not be as interested.
TheFilmProphet you argued Chameleon will provide personal troubles while the other villain will provide the action.
There is only one guy who is going to provide the personal problems to Peter and that's Harry.Thomas Church's villain will provide the action etc.Harry is going to be the personal antagonist.Not the Chameleon disguised as some college professor.
How visually stunning would the Chameleon be??? How about not at all.But if we get Sandman and Harry becoming a Goblin then you get instant success.
Now that's the common sense part done.Let's talk rumours/speculation.
Heres a couple of links for Church as Sandman: http://www.efavata.com/CBM/Spiderman3.htm
This one mentions Tobey Maguire's Sandman comments in Wizard too: http://filmforce.ign.com/articles/597/597982p1.html
http://www.themovieblog.com/archives/2005/05/topher_grace_in_spiderman_3.html
See I can dig up rumours too.All speculation.But the Sandman theorey has two things going for it.
1.Raimi and Maguire like and want Sandman.
2.Church looks like Sandman.
There now I can debate as good as anyone else.You want to stay civil with me Prophet then don't make silly remarks about pitying me etc.That's when my manners go out the window.