"For the first time, the thought entered Vader's consciousness that his son might best him. He was astounded by the strength Luke had acquired since their last duel, in the Cloud City - not to mention the boy's timing, which was honed to a thought's-breadth. This was an unexpected circumstance. Unexpected and unwelcome. Vader felt humiliation crawling in on the tail of his first reaction, which was surprise, and his second, which was fear. And then the edge of the humiliation curled up, to reveal bald anger. And now he wanted revenge."
The quote from the novel shows that Vader actually saw that Luke was powerful enough when using his aggression to defeat him. Who could Luke contend with in the ROTS error?
__________________ Introduce a little government. Upset the established gangs, and everything becomes order...
Democracy is the very definition of awesome.
I'd put a Nexu above RoTJ Luke. Against Padme, Luke's going down. Plus she's hot.
__________________ Recently Produced and Distributed Young but High-Ranking Political Figure of Royal Ancestry within the Modern American Town Affectionately Referred To as Bel-Air.
Beg your pardon, but how does that reflect badly on Luke in any way?
Firstly, in that novel Luke was still gaining confidence in himself and wasn't yet at his peak.
Secondly the Nightsisters are nothing to scoff at. They managed to repel an attack by several Jedi, including YODA! Plus one of them held her own against Darth Maul in combat.
Thirdly, that wasn't just any Nightsister. That was Gethzerion. SIDIOUS was afraid of Gethzerion. So afraid that he stranded a garrison of troops on Dathomir to keep her from leaving the planet.