I don't have the problems you do with these scenes because the Anakin of the PT really is a pretty big idiot, so I don't see why it's so unlikely that Palpatine would be able to so easily manipulate him like he does.
Doesnt the fact that Anakin is
that stupid mean that scenes with him in can never be good? Lets look at the Shakespeare reference. In a tragedy, theres often a totally stupid character who is tricked by the antagonist, but these scenes are mostly played for comedy, or to illustrate something about the antagonist prior to their manipulation of the protagonist. The interesting part of the story is how a character can crawl under the skin of another very accomplished and intelligent character and start to screw them up with clever manipulation.
That cant happen with Anakin, so I dont see how you cant have the same problem with these scenes.
I still cannot make the connection between the "weak-minded, easily duped, desperate for acceptance" PT Anakin and the "focused, take control of the situation" OT Vader. Guess that happened off-screen...
As far as I concerned, the one saving grace of the PT is that they are so awful, and so disconnected from anything we ever see in the OT, that they manage not to screw the OT up for me. Ive tried looking at Vader and thinking of him as Anakin, but it just doesnt happen. Theyre two totally seperate trilogies which happen to have the same name.