I don't get this bit. Vader wants revenge for Death Star 1, plus he wants to stop Luke from getting anywhere near the Emperor because Luke can destroy the Emperor ... so if Vader's twin motivations regarding Luke are to waste him, why does he want to tease him off the gantry?
At the start of ESB Vader wanted to rid the alliance of Luke - he's the new poster boy who destroyed the Death Star.
When The Emperor gives him a call and says Luke could destroy them, Vader said how about we turn him instead, Eperor said "yup, that might work, get on it." Now Vader's motivation has changed.
The whole Bespin set-up and testing of the carbon freeze chamber showed Vader had every intention of getting Luke in front of the emperor so they could turn him. "I do not wish the emperor's prize to be damaged, we will test it on Captain Solo." Vader was taking Luke to the Emperor.
Vader's plan was to confront Luke, beat him into submission and carbon freeze him. But when Luke proves to be more powerful than Vader anticipated, fights back but is ultimately beaten down onto the gantry Vader has to coax him back by sweet talking him and plays his trump card "no, I am your father" this knocks Luke for six and Vader continues "you and me can destroy the emperor, that's what you want, right? We can rule and shit." Luke's temped but thinks "fuck it." and bails.