You guys are making WAY too much of 'what the Emperor was thinking.' One thing that was clarified in ep3 was that with the sith, everybody fuks everybody over. You totally screw your master over, or your aprentice, or just about anyone else. We also saw this in the OT where both Vader and the Emperor Luke a job at the expense of the other. I don't think we need to look deeper into the mind of Palpatine... He is a bastard period. He wanted Luke dead or at his side with Vader dead... Made no difference to him.