That Dooku thing, whilst echoing of Saruman as well, does sound credible.
There is a lot of this stuff out therer now coming in from Hyperspace webchats (with people observing the filming), much of which is VERY spoilerish, so watch it...
(taken from Tfn):
"The Death Star plans are not really important in Ep3. The focus of Ep3 is on more important story points."
"The Dagobah cave was explained in Ep5, does not need further explanation, and [fans should] focus energies on other things." (yayyy!)
"The "no disintegrations" line will not be explained in Ep3" (double yayyy!)
"The "force ghost" theory will be explained" (it had better be)
There will be no doubt left in the film that Anakin is Vader, for those who thought that would be kept 'obscure' for those watching the films in chronological order.
"Anakin knows Padme is pregnant and expecting." (BIG reveal, that...)
There, that should provide some discussion for a while...
Just ro re-iterate, this stuff is fact, not rumour, from the official sw.com Hyperspace service; the words are Pablo Hidalgo's, who is watching the filming (but he is being vetted by Lucasfilm to not give too much away)