Deathstroke #27 presents a new origin and history for Terra, starting with her time as a princess of Markovia from which she was forced to flee for her life, leaving her privileged life and family -- including her brother Brion, AKA Geo-Force -- behind. From there, she travelled to America where she found herself an able conwoman and was recruited by Deathstroke to bring down the Teen Titans from within.
While we do see Terra’s attempts to seduce Deathstroke, the comic is clear that Deathstroke does not reciprocate, and he absolutely does not sleep with the underage girl. However, we also see that “The Judas Contract” plays out in a new way -- we already knew things between Deathstroke and the Titans went down differently in “The Lazarus Contract” crossover, and now we learn that, unlike in Mark Wolfman and George Perez’s classic story, Terra survives. To keep her from killing the pair of them, Deathstroke is forced to calm her down by returning her affections, and while it was a matter of survival, it still crosses a line.
The important thing about the retcon in Deathstroke #27 is that while it doesn’t absolve Deathstroke of his actions, it changes the history of the character just enough. He’s still a monster, and what he does to Terra is unforgivable, but it’s more in line with what we expect from superhero comics. We even see Deathstroke’s oldest friend Wintergreen condemn Slade for his manipulation of Terra, saying, “Even in our business there’s a line. You’ve crossed it.” and Slade knows he has as well.
Slade Wilson is not a good person, that’s been a core theme of Deathstroke since the start of DC Rebirth. Christopher Priest doesn’t seem to want to undo the awful things from Slade’s past, but the small changes to the character’s history do put certain actions into context and, if anything, it reinforces “The Judas Contract” rather than diminishes it. Slade manipulated a powerful teenage girl into doing his bidding, and that will always be part of his character, but now we have a larger frame of reference to see why he did it, and that makes him more of a villain than ever.