Originally posted by StiltmanFTW
Luke was conflicted with his own dark side, realizing it takes away his humanity.Both father and son were conflicted in the throne room scene, in their own ways.
I mean he was tempted by the dark side, sure. That was mostly when he was hiding and avoiding the fight though.
The entire movie however Vader was conflicted. Luke says it. Palpatine even questions it.
Vader was loyal to Sidious because he thought there is no other way imo. Not because of any true loyality.
Vader still being a darksider doesn't mean he can't be hugely weakened by conflict. He can be 51% dark side and 49% light to put in in numbers. In TFA Kylo was trying to convert Rey (just as Vader was trying to convert Luke), but we know he was extremly weakened by conflict.
I think both Luke and Vader were significantly conflicted.
Or Vader could have been 99.9% dark side and .1% light side at the onset... We don't know either way. Not all conflict is created equal.
So until we get some legitimate confirmation that Vader was massively conflicted during RotJ, I don't really feel confident in assuming that his power was intended to be significantly hindered by default.
But given the fluidity of new canon, it's always subject to change.