RWBY - Adam Taurus And Darth Vader

Regarding Vader, Luke tries to see the best in him but in later material his sister argues that he is being foolish as no matter how good he once was his acts of cruelty eventually outweighed his acts of kindness and in the end all anyone will ever remember is hes the psychotic bastard that blew up a planet!
In regards to Sasuke, that is something of poor writing, the writer admitted when he first started the series his intended ending was Naruto and Sasuke would be friends at the end, and so no matter what perverse acts he decided to make Sasuke do they were always going to become friends again because he already decided so, and he swore no matter what he wouldn't deviate from his chosen conclusion, regardless of plot or character development.
Sasuke murders innocent people, attempts to openly assassinate the leaders of the five main villages, tries numerous times to kill Naruto himself. He physically, emotionally, and psychologically abuses Sakura, and then pretends to be narutos ally again only to reveal his plan was to murder him all along. And then poof they're friends again. After they blew off each others arms.

But the key thing to remember is that in the beginning they were both good people.

As for Adam, he resorts to murder and violence simply because he wants to, he is part of an organization that strives for equality but he is trying to turn it into RWBY's version of the nazis because of his big superiority complex. At first Blake thought Adam had the right idea with using extreme means to send the White Fangs message, but when she realized he held no true concern for the lives of the innocent, no matter who they may be, she left because he frightened her. Now Adam wants to slowly destroy everything in her life before he kills her. And his dialogue shows he never truly cared for her, he simply objectifies her, views her as something to possess.

What separates Adam from the two examples you used are Vader did at some point care for the well being of his children before turning to the dark side, Sasuke was at one point Naruto's best friend. But Adam never truly cared about Blake, he sees her as an object he wanted but didn't get and is throwing a tantrum, hell he tried to murder her parents simply because she told on him.

So to answer your question. FUCK ADAM!